Free Exchange Email Client For Mac

Some people say you should stop using desktop email clients. I get where they’re coming from. Web-based email services have come a long way over the past decade, and many of them are feature-rich enough to be on par with desktop-based alternatives.

But there are several valid reasons to keep using desktop email software, and I believe desktop email clients will never be obsolete.

Postbox and Microsoft Outlook are the two main options, but they’re pricey. If you only need an email client to handle one or two personal accounts, then a free email client will likely serve you just fine. Here are the best free desktop email clients we’ve found.

My personal email client of choice is Mutt with one caveat: For the occasional meeting invitation sent by an Exchange server, I will fire up Thunderbird with Lightening to answer it, and then close it immediately since it is wasting so much RAM with it’s bloated “trying to do everything” architecture.

1. Thunderbird

Available for Windows, Mac, Linux.

Although Thunderbird development was “discontinued” back in 2012, it still receives maintenance updates so don’t write it off as dead. In fact, as of this writing, the latest release (version 60.2.1) came out in October 2018. Sure, Thunderbird may not be getting new features going forward, but it’s absolutely still viable for everyday personal use.

And, as sad as it is to say, Thunderbird is the only free and open-source desktop email client that’s actually worth using. Other open-source clients exist, but they’re riddled with issues like clunky interfaces, glitchy performance, and a lack of advanced features.

If you’re adamant about never spending a penny and never switching to a web-based email client, then Thunderbird is your best option. It can do pretty much anything you need, including setting up message filters, autoresponding to emails, and several other nifty Thunderbird tips and tweaks.

Download:Thunderbird (Free)

2. Mailspring

Available for Windows, Mac, Linux.

Back in 2016, Nylas Mail hit the scene and looked as if it’d be the desktop email client to put all other desktop email clients to shame. But then in August 2017, the team announced that they’d no longer be working on Nylas Mail and opened up the source to the public.

One of the original authors then forked the project and relaunched Nylas Mail as Mailspring. He optimized and improved many of the internal components, resulting in quicker syncing, less RAM usage, faster launch times, and more.

Thunderbird may be the client of choice for those who want reliability and time-tested staying power, but Mailspring is the client to use if you want something fresh, new, exciting, and full of future potential. It’s free to use indefinitely with some advanced features locked behind a subscription.

Notable Free Version Features

  • Syncs with Gmail, Office 365, Yahoo, iCloud, FastMail, and IMAP.
  • Unlimited email accounts and unified inbox.
  • Undo sent emails within a given period of time.
  • Support for pre-built themes, layouts, and emojis.

Notable Pro Version Features

  • Powerful template support for productivity.
  • Track whether emails are opened and links are clicked.
  • Schedule emails to be sent at a future time.
  • Snooze emails and create follow-up reminders.
  • Share email threads with others using a web link.

Download:Mailspring (Free, Pro for $8/mo)

3. Sylpheed

Available for Windows, Mac, Linux.

Sylpheed is a desktop email client that’s been around since 2001. While it does feel dated compared to modern email clients, it’s not bad by any stretch. In fact, its old-school interface and approach to email management may actually prove helpful if your email habits are causing undue stress6 Simple Tricks to Reduce Email Stress6 Simple Tricks to Reduce Email StressDealing with email is the best part of my day. Said no one ever. You need all the tips you can get to manage your email inbox? We can help you out!Read More.

The best thing about Sylpheed is that it knows what it is: an email client. It doesn’t concern itself with tons of extraneous features that bloat the installation and clutter the interface. Sylpheed is simple, lightweight, and full-featured.

Notable features include fast launch and overall performance, advanced email search and filters, effective junk mail control, encryption, and extensibility through plugins.

Download:Sylpheed (Free)

4. Mailbird

Available for Windows.

Mailbird is an attempt to optimize the desktop email client experience.

If you’ve never used desktop email before, then you’ll probably love Mailbird. If you’re migrating from another client, it will be hit or miss—some parts will feel familiar, other bits will impress you, but you’ll undoubtedly find aspects that you hate as well.

All we can recommend is giving it a try. It’s definitely slick and modern, and there’s a lot to like about it. Note that it’s a freemium app so the free version is restricted in some ways.

Notable Free Version Features

  • Beautifully sleek and minimal interface.
  • Syncs with any IMAP or POP email service.
  • Lightning fast search and indexing.
  • Integration with Dropbox, Evernote, Google Docs, and more.
  • Supports up to 3 email accounts.

Notable Pro Version Features

  • Unlimited email accounts and unified inbox.
  • Snooze emails and set up reminders.
  • Speed reader for emails.
  • Quick preview for email attachments.

Free Exchange Email Client For Mac

Download:Mailbird (Free, Pro for $18/year or $59 one-time purchase)

5. eM Client

Available for Windows.

eM Client aims to be an all-in-one solution for dealing with office tasks and communications. It’s primarily designed for email, but also has nifty calendar integration, task management, contacts organization, and even chat support—and the free version only has one (albeit major) limitation, as you can see below.

Notable Free Version Features

  • Slick Modern UI interface that fits well with Microsoft apps.
  • Syncs with Gmail, Exchange, iCloud, Office 365, and Outlook.com.
  • Conversational view for email threads.
  • Integration with all common chat services, including Jabber.
  • Supports up to 2 email accounts.

Notable Pro Version Features

  • Supports an unlimited number of email accounts.
  • Can be used for commercial purposes (e.g. business office use).
  • VIP support and troubleshooting.

Download:eM Client (Free, $50 one-time purchase)

Windows and Mac Have Built-In Email Apps

All of these free desktop email clients are fantastic so don’t fret too much. They can all get the job done, so give each one a try and stick to the one you like best. As for me? I’ve been using the free version of Mailspring for months and I’m quite happy with it.

If the above apps seem too complex for your email needs, then you can always resort to the Mail app that comes pre-installed on Windows 10. Some consider it bloatware while others think Windows 10 Mail is worth using. In any case, Mail is the simpler of the two Microsoft email apps. And if you have an Android phone, get one of the best email appsThe 10 Best Email Apps for Android, ComparedThe 10 Best Email Apps for Android, ComparedEmail on a smartphone? Use one of these excellent email apps for Android to make the experience more productive and enjoyable.Read More to complement your Windows client.

And for a better computer experience, have you considered building a DIY desk7 DIY Computer Desk Projects That'll Save You Money7 DIY Computer Desk Projects That'll Save You MoneyNeed a computer desk on a budget? Here are some excellent DIY computer desk projects you can build yourself.Read More?

Explore more about: Desktop Email Client, Email Tips, Mozilla Thunderbird.

  1. Mailbird no longer has a free version

  2. I've been looking for a client that lets you download all the attachments at the same time, to a folder, like selecting several mails, clicking on 'save as' and that's it, so I don't have to manually download 50 pdf files from 50 different emails. I still haven't found what I'm looking for. I've read thunderbird had a third party plugin that did it but now it doesn't work anymore. I think even netscape communicator 4 on win9x back in 98 o 99 could do it. why can't modern clients do it?.

  3. I think the best feature about Thunderbird, which is absent in all other clients, is the ability to delete only the Attachment in the Email. I retain the actual Email with only the Attachment name, and not the actual attachment file. For example, when we send an Email to clients, we attach relevant Datasheets / Brochures of the products, our company profile, etc., which makes the Email 2-3 MB large. But later, I simply delete the Attachments from the Sent items, making the Email shrink to 30-40 KB. This is a very useful feature which I think all Email Clients should have.

  4. Hi
    Like everybody in the world I receive dozens of attachments (doc, excel, pdf....) everyday.
    So I use the ONLY email client in the world which is able to PREVIEW attachments (WITHOUT opening dedicated software like word or excel or acrobat) with only ONE click INSIDE the email window.
    And I save time everyday
    Best regards

  5. I use Thunderbird for backing up my Hotmail & Gmail, but I find it slow to use as a regular Client so I still access my Hotmail via Outlook Live online. I get up to 50 emails a day and immediately toss half - it's mainly for Social Media.
    I still prefer to use OperaMail as my Client for Gmail (it's a separate program now) because I find Gmail online to be a non-intuitive PITA and with OperaMail I can have it in the same layout as forever. It's a bit buggy once in a while, but way more effective for me. I get a couple 100 emails a day - personal and hobbies - and I also access my RSS Feeds from it (which alone is worth having it). Tagging is easy.

  6. Another component in favor of Thunderbird: because of its addon ecosystem, it's possible to integrate seemingly unrelated messaging tools like Google Hangouts or Voice. This can be helpful if you find yourself keeping many browser tabs open just for communication; at least you can centralize everything in one place!

  7. I was a home user of Outlook Express email until they went to Microsoft Live and continued to use it until it just didn't work. It was perfectly functional for all that I needed on my home computer (Outlook Client for work email). A few years back as Windows moved on, I tried Thunderbird, and it just didn't have enough features of what I used to keep me happy. I switched to eM Client (about 3 years ago) and have never turned back. I've had no problems and it does everything I need it to do.

  8. I started using Thunberbird a few months ago when my Windows Live started gliching when trying to receive e-mails. Kept showing a message saying it could not connect to the server - and I had a TON of folders with saved stuff on there too.

    Downloaded Thunderbird and for the most part, it is great. I do HATE that you can only enter one e-mail address on a line at at time. Ridiculous! I am also having HUGE issues with it flagging e-mail as junk from people I work with who send e-mails ALL the time. I have 'trained' it and flagged these e-mails as not junk and even went into settings and made sure the address books are checked so it SHOULD ignore those e-mail address. Nope, still flagging them as junk. Would love to have this fixed but am about to try a different program! GRRR!!

  9. I'm using Thunderbird. However, last week, Quickbooks stopped communicating with Thunderbird, and wouldn't send invoices... on only ONE of my computers. The other one is still working fine. So, my question is - which of these programs have you used with Quickbooks?

  10. all my efforts to make the W10 email app behave better have failed. I got into a very expensive act of buying 2 plane tickets because the W10 email consistently faile sin searching for emails with any key word. In addition, there is no quick way to configure it the way you want. It is quite possible, power users will claim 'I do not know how to use it'...well, this statement itself is the proof of my claim! In my iPhone, safari shows I have 16000 emails correctly. & I found the earlier eticket sent to me but not in the W10(is it 'outlook'?) while for not apparent reason, W10 email chose to show only 3659 of them! ...So I am done using it!

  11. I have been using Thunderbird.
    I really like that the inbox uses columns for Date, Subject, From, To, and more that I can sort on after selecting a message.
    I really don't like that when creating an email the To, CC, BCC only accept one address per line, so you can only see a small portion of the recipients in a long list.
    This increases the chance of sending something to the wrong person. It's also really hard to enter long mailing lists.

    Can someone recommend an alternative that does both well?

  12. Which do you use?

  13. General concerns about the email clients? I could do this myself (perhaps) but thought maybe by me posting a comment others might benefit. Since Windows 10 Pro is more accommodating on then the Home edition I would like to know the following:

    First issue: Which of these programs are accepted by Windows 10 Pro and will survive a Microsoft 'Update' ?

    Secound issue: I'm concerned about migrating my 32bit versions of Windows OUTLOOK EXPRESS

    ron

  14. Please add Hexamail Flow too!

    • Tried Hexamail Flow. It won't allow me to add a single account. It cries that 'All accounts must have a unique name', but this is the first account. Nothing will satisfy the program as a name. I've even tried naming it something like 'liedrfkhugjklsdghjf' and it doesn't work.

      Mailbird allows only one account unless you buy it. They should make this clear when they advertise 'Have ALL your accounts in one client. FREE DOWNLOAD'. Very unscrupulous advertising.

      I've purchased email clients before, but I don't think I should have to keep buying the program every year, but they conveniently break the programs and require you to buy them again for support. I just want one good program.

  15. Does anyone know of any email client that will allow one assign a color category to an inbox email AND sort on it? I can't believe Outlook 2016 will not do this UNLESS it's a POP account. Thank you.

    • Hexamail Flow allows labels to be coloured and sort on labels.

      • Thank you so much!

  16. Thank you for introducing me Nylas Mail. I was exactly looking for this. From my day beginning, I've started to search for best email client like Thunderbird. I'm running two different companies so I want to use two different email client software. You made my day author... Thank you!

  17. Having used email clients (Pinemail_ before there was a web-based Internet and once the WWW appeared, I tried web-based mail programs.

    The major difference is SECURITY. Webmail is just that, the etch-a-sketch version of real email and like any browser going to any web site (webmail is web-page based), are easily hacked. Webmail, using the forced browser upgrades tied in with the latest HTML5 layers, Stalkers like canvas fingerprinting can now monitor your email, follow your email, and invade your privacy much easier than a real email client.

    Your Privacy, and Security are only available buy using a real email account on a real email client. Using a web browser to read/send/ webmail is like writing notes in a diary with a World Wide Web camera over your shoulder.

    • if you ever want a super-secure web mail client, including an on line keyboard so keystrokes can't be recorded, check out safe-mail dot com (or dot org I don't recall which).

      there are only 1-2 glitches I've encountered (I don't use it regularly now, but did in the past when I needed 100% security that cost $0).

      one major glitch is that the FBI blocked access somehow until the server agreed to let them have access on demand. It's not a USA based company. This went on for a few months but apparently they gave in.

      Second glitch I encountered a couple years ago, it may be resolved now, is that late night access was extremely slow.
      I know very little about networking etc so can only guess why...performance was fine during the day.

      Interface is minimalist, no ads, free access has limited storage space, only supports maybe3-4 languages--English Hebrew Japanese and I think Mandarin?
      Paid version comes in tiers depending on needs. Has quite a few features like Google--calendar, a few other things. Encrypted enough to send medical or financial data. Also probably things like child porn—but that's the price of freedom I suppose.

  18. Hiri is a paid client. It is not free.

  19. i believe Nylas mail are pretty much dead now.

  20. I am looking for a replacement to EM Client version 7. Version 6 was good but the way they handle multiple replies on version 7 has serious problems

  21. Nothing but problems with Em Client. This week recent emails started flashing in my Inbox making it impossible to click on them. That was the last straw....finding another tool now!

  22. NONE of these email apps are FREE!
    Hiri is only free for 14 days!
    The rest give a limited number of free trial days, and only 2-3 email accounts!
    WHY DO YOU LIE?

    • Yes, you are right. Reviews are not reflecting the truth.
      I don't know what's the point except that the site is gonna lose customer base.
      I'm definitively stopping my visits.

    • Thunderbird is free.

      • WHEN I GOT A NEW USED PROCESSOR A COUPLE OF YEARS AGO, IT DID NOT HAVE INCLUDED OUTLOOK EXPRESS THAT MY PREVIOUS COMPUTER HAD.
        THUNDERBIRD IS A ROYAL PAIN IN THE REAR END.
        I CLICK ON AN EMAIL & IT POPS UP, I CLICK IT OFF AND WHAT I JUST CLICKED ON IN THE PANE, IS NOW MOVED BACK TWO PACES TO A DIFFERENT EMAIL.
        WHEN I TRY TO DELETE A FEW EMAILS AT A TIME...UP POPS A SERIES OF EMAILS, SO I HAVE TO STOP & CLICK THEM ALL OFF, IN ORDER TO GET BACK TO WHAT I WAS DOING...I AM SO OVER WITH THUNDERBIRD.
        BUT, I HAVE NUMEROUS FOLDERS NOW & DON'T KNOW WHAT TO DO OR WHAT FREE INBOX IS OUT THERE & WHETHER I CAN EXPORT ALL MY EMAILS & FOLDERS TO A NEW FREE INBOX.
        OUTLOOK IS OVER 80 BUCKS HERE IN VANCOUVER...TO BUY THE PROGRAM...I DON'T KNOW IF I WANT TO SPEND THAT KIND OF MONEY ON AN EMAIL PROGRAM...SEEMS LIKE A LUXURY I CANNOT AFFORD.
        WHAT SUGGESTIONS MIGHT ANYONE HAVE & ANY SOLUTIONS OR FIXES FOR THUNDERBIRD, IF THERE ARE ANY, IF THERE IS NO PROGRAM THAT I CAN IMPORT EVERYTHING TO THAT'S FREE.
        THANKYOU,
        LAYNA.

        • I am running away from Thunderbird as fast as possible. Here are the problems I found.
          It began to lose folders. I save all my email locally in a long list of folders. I've done it for decades. For no reason I can figure out, in 2018, version 52.52, folders began to disappear from the folder pane. Funny thing is, they still exist if I search for them, and I could search so as to get all the emails and then copy them to a new folder. Then that folder disappeared too, so I did it again with a new folder in a different place in the hierarchy. Today my TRASH folder disappeared.
          Suddenly T-bird stopped downloading my emails. It just began to say 'No new messages' when there are hundreds. Even stranger - it finds one or two messages that it can download, but all the rest are invisible. The ones it downloads have nothing in common I can see. A google search shows none of these problems are unique.
          Mozilla provides no real help. The 'fixes' are all high tech programming changes that leave me in the dust. You can't interact with the forum without registering which is a constant nightmare. The password is always deleting with time and you can't put in a new one without being told 'that email address is already in use' (yes, because it's mine, fool). Then you have to sift through hundreds of postings to find what - usually nothing! Mozilla doesn't want to hear from you about your little problems.
          Constant problem - you can find a particular email, and it will tell you what folder it's in - but good luck finding that folder if you have extensive folders and subfolders. There is no help at all. No way to figure out where you stashed that folder. I've spent hours searching for a single folder.
          Last problem - If you go to File Explorer to see where your data is stored - good luck. T-bird's scheme for storing its data in mixed up msf and sbd files is from some other planet. Some T-bird folder names have corresponding files but others don't and their contents have some of the saved emails but not others. It's all a complete mystery. If you want to save a good folder for later possible use, you have no idea of what to save, or how to restore anything by pasting it back again. If I could find an identifiable file with emails, that would be great, but I can't.
          So sayonara T-bird. You are mysterious and unworkable unless you are just working perfectly without problems. And that is just a memory now.

    • This is because these people never really test any of these 'Top' application lists. They just gather names from a search engine and post them in some random order.

      • Try Hexamail Flow - it is COMPLETELY FREE to use for multiple accounts.

        We only request you purchase if if you really like it to allow us to continue to invest in its development!

        • Yes, I tried your program. It just doesn't work.

          Can't add ANY email accounts. It pops up with an error:

          'All account names must be unique'

          Only one account and no text at all will satisfy this requirement.

  23. I've been searching for years for the best email client with these added requirements: a calendar/scheduler, tasks, events, contacts, highly configurable, securable, 'open source' (No Freemium) and fully portable at portableapps.com. I tried Operamail which I found to be a very good email and contacts client, but no calendar, etc., although I have no idea if anything has changed since being bought by Chinese owners.

    Then I tried Thunderbird was too 'clunky' and slow for me. I liked Seamonkey more and I've been using for the last four years. It has email, a calendar, tasks, events, contacts, a browser and more; most of which need add-ons to make them more usable to each users needs.

    It works quite well, still gets updated once a year or so (which is just fine for me), has a small dedicated team and an online extensions configurator to modify many T-bird & FFox extensions to work with it. I recommend users install exts's in small batches for troubleshooting any incompatibility issues that may arise. I'm still fussing with the address book fields and tasks/events to work with specific calendars though, but I've truly not found any better email client and if T-bird is no longer being developed I guess I'll stick with Seamonkey.

  24. I would strongly urge you to not use MailBird. They 'phone home' all your emails and have even publicly stated that it is not illegal to do so and are continuing. In their newer versions they added an 'opt out' feature but it still phones home. You can use any packet sniffer to see for yourself.

    • Thanks for the tip. I downloaded it and removed it straight away because it is NOT free. Only the trial period is.

  25. The free version of EssentialPIM is also a possibility.

  26. A little fact checking would be nice.

    First, its funny that you suggest the non-free Postbox as one of the two 'main' options, then make false claims (see below) about Thunderbird, apparently unaware that Postbox is a Thunderbird derivative, and is currently based on a very OLD version of Thunderbird.

    What false claims? Well, Thunderbird development is far from dead. It has received more new features and bug fixes since Mozilla pulled its developers off of the main project (Mozilla still provides considerable infrastructure support) than it did in the previous 5 years under Mozilla's umbrella.

    They also recently started receiving donations, and as of the last Treasury Report I saw, from November 2016, they were averaging about $70,000 per MONTH, most of these from small, one person donations.

    Current Thunderbird leadership (an elected Council) is considering the options for a new home - the SFC (Software Freedom Conservancy and The Document Foundations being the two main contenders I believe.

    So, the user base is definitely supportive of Thunderbird, and as far as I'm concerned, the future's so bright, you have to wear shades.

    • Yeah. I've got Thunderbird release 45.7.1 that came out on...FEBRUARY 7, 2017.

      MUO should strive to be better than SCROTUS (So-Called Ruler Of The United States).

      • FU asshole

    • Thanks Charles! I'll definitely try Thunderbird again, I still have it and I surmise it gets updated through my portableapps.com menu which I love. I view Mozilla as a similar open source version of google in that they both work on a lot of projects which come, change often and go and sometimes come again. But Mozilla gets my support. Please let me know your thoughts on Seamonkey.

      I agree with you also that 'A little fact checking would be nice.', especially when you're a professional article writer and reviewer. I almost feel duped!

    • I would really like Thunderbird except that it requires you to use a new line for each address entered in the To, CC, BCC fields. This is so silly, because with one address per line, you can only see a small portion of a long list at a time.
      It also makes it really hard to add a lot of recipients. I can't understand why they do this in an otherwise really good product.

  27. I am still using Eudora, which is the best email client ever.

    A year or so ago it started choking on Google certificates. I looked around for another email client and could not find even one that was as good as Eudora. Fortunately some enterprising techie found a way to force Eudora to accept those certificates that Google has been cranking out at least once a week since then, so I'm happy.

    • You should wake up honestly...

    • Oh lord, Eudora .. not heard of that since the late 90s... that is a relic for sure. I worked for an internet provider and we used to provide it with our DIALUP accounts pre-configured. It was junk, we eventually stopped supporting it all together.

      I didn't think that junk still existed..

    • And I would still be using Eudora if my university had not shut down the POP-server. I never got Eudora to work satisfactorily with IMAP. Unfortunately. I fully agree that it is the best mail client I've ever used, and I'm desperately looking for an email client even half as good. Since having to let Eudora go, I suddenly understand all my colleague's email woes. I am definitely much less productive with managing my emails now...

      • I started using Eudora back in the nineties. I used it for many years and would be using it yet if some geeky jerks hadn't killed it. I don't know why anyone would want better standalone email than Eudora.
        I don't know how much longer we're gonna have email, anyway. Things I'm hearing lately give me to think email is gonna be bound and gagged ere too much longer: THE RUSSIANS ARE COMING! THE RUSSIANS ARE COMING! THE RUSSIANS ARE COMING! EEEEEEEEEKK! HIDE THE MONEY! GIVE THEM THE CHILDREN INSTEAD!

        • omg too funny... thx for the morning pmu :))

    • Yes of course, I agree with you 100%: Eudora (v. 6.3 for me) is still the best email client that was ever made available to an immense piblic, and that kept working so well for so long (more than 18 years for me).
      I'm also starting to have problems with 'bad certificates' and would be very interested to know how your Eudora was forced to accept them (or rather, convince the POP server to agree to establish a valid communication with my PC-based, Win7, Eudora...)
      Thanks if you can help!

Before you begin

  • OS X Snow Leopard and later support Exchange Web Services (EWS) as a connection to your Exchange server. If your Exchange server does not use EWS, check with your Exchange administrator to see if an IMAP connection to the server is available instead.
  • If you're using macOS High Sierra or later, your Exchange server must use Exchange Server 2010 or later with the latest service pack installed.
  • If you're using macOS Sierra or earlier, your Exchange server must use Exchange Server 2007 or later. With Exchange Server 2007, you must also have Service Pack 1 with Update Rollup 4 or later installed.
  • For best results, make sure that your software is up to date before setting up an Exchange account in Mail.

Add an Exchange (EWS) account to Mail

Follow these steps to add an Exchange account to Mail. You can add as many Exchange (EWS) accounts as you want.

  1. Open Mail.
  2. From the Mail menu, choose Preferences, then click Accounts.
  3. Click the Add button (+) to add an account.
  4. Select Exchange from the list of account types, then click Continue.
  5. Enter your name, email address, and password, then click Continue.
  6. If Autodiscovery isn't enabled on your Exchange server, you're asked to enter your server address, then click Continue. If you don't know the server address, contact your Exchange administrator.
  7. Features such as contacts and calendars can also be used with Exchange. Select the options you want to use, then click Continue.
  8. In earlier versions of macOS, a summary sheet appears when you complete setup. If the summary is correct, click Create. If you need to make changes, click Go Back. Select 'Take account online' to start using the Exchange account.
For

If new messages don't appear in your Exchange mailbox

  1. If certificate authentication is enabled on the mail server, make sure that your mailbox has no more than 11,000 messages. Microsoft recommends no more than 5000 messages per Exchange mailbox.
  2. If that isn't the issue, quit Mail, then open it again and don't select any other mailbox while Mail gets new messages. To be sure that Mail has finished downloading and indexing new messages, you can choose Window > Activity, then watch the progress of the download.

If you can't send messages from your Exchange account when SSL enabled

The SSL port setting in Mail preferences may be incorrect for your Exchange account. Check with your Exchange administrator for the correct SSL port setting.

If you can't send or receive email or connect to the Exchange server after upgrading your Mac operating system

OS X Mountain Lion v10.8 and later use the Exchange Autodiscover service, which allows Mail to automatically get setup information from the Exchange server. If your Exchange server isn't providing the needed setup information, contact your Exchange administrator.

Evolution Email Client

If necessary, you can turn off Autodiscover:

Free Exchange Email Client

  1. Choose Mail > Preferences and go to the Accounts pane.
  2. Select your Exchange account from the list of accounts.
  3. Click the Server Settings tab.
  4. Deselect the 'Automatically manage connection settings' checkbox.

You can then enter the internal and external server information manually.