Outlook is not responding, has stopped working, freezes or hangs

If you find that your Outlook has stopped working, is not responding, or freezes or frequently hangs on Windows 10/8/7, then this post suggests some troubleshooting steps you can try. While it is always a good idea to optimize & speed up Outlook from time to time, you may at some time face this issue.

Outlook is not responding

1] Run Microsoft Outlook in Safe Mode, without add-ins. To do this, open Run box from the WinX Menu, type outlook /safe and hit Enter. If Outlook does not give you any problems, it is possible that one of its add-ins is creating problems. Take a look at your installed Outlook add-ins and disable them selectively, in order to find the offender.

2] Disable hardware graphics acceleration for Outlook and see if this helps. To do this, open Outlook program > File > Options > Mail > Compose messages > Editor Options button > Advanced.

Outlook has stopped working, is not responding, freezes or hangs

Here under Display section, check the Disable hardware graphics acceleration box and click on OK/Apply and Exit. Restart your Outlook and see. If it makes the issue go away, then its probably some issue with your video driver. Update it and see.

Hardware Acceleration uses computer’s hardware for performing a certain task and function faster than would be possible using software. But this creates issues for some people. So turning it off is one thing you can try if you receive a Program not responding message.

One thing you want to know is that when you disable Hardware Acceleration for Outlook, it gets turned off for all Office programs.

3] At the time, your Outlook may be busy carrying out some other processes, like synchronizing your email, archiving old items, etc. At such times, Outlook may respond slowly. In such situations, it’s best to let Outlook complete its task.

4] If you have a huge Outlook data folder, then this can cause temporary freezes as Outlook takes time to open each email or data folder.  These Outlook data files may be either personal folders (.pst) files or offline folder (.ost) files.

The expected behavior is as follows, depending on your .pst or .ost data file size.:

  • Up to 5 GB: Good user experience on most hardware.
  • 5 to 10 GB: If you have a fast hard disk and lots of RAM, your experience will good. On others, you may experience application pauses till the drives respond.
  • 10 to 25 GB: When the .ost file touched this figure, expect frequent pauses on most hard disks.
  • 25 GB or larger: If your .ost file crosses this size, pauses or freezes may be expected, especially while you are downloading new email messages or synchronizing many RSS feeds.

So if you can, delete your unwanted email to reduce the size and ensure that auto-archiving of old Outlook items is enabled.

5] There is one more thing you could do. Microsoft has provided Inbox Repair Tool as well as a Fix It, which lets you recover folders and items from corrupted Personal Folders or .pst files. It can even recover items from an offline folder or .ost files. The OST Integrity Check Tool will help you fix corrupted .ost files. Use the Inbox Repair Tool or Scanpst.exe to repair & optimize your Outlook data.

6] There are also a few command switches that can help you reset, restore or fix certain Outlook functions. Take a look at this post –  Troubleshoot Microsoft Outlook problems, to learn more about this.

7] Use the Microsoft Office Configuration Analyzer Tool. It provides a detailed report of your installed Office programs and highlights known problems.

8] If you receive Outlook has encountered a problem and needs to close error, cleaning your Outlook Profile is an option you can consider.

9] This post will show you how to repair an Outlook account if your Outlook not syncing.

10] See this post receive Cannot start Microsoft Outlook, Cannot open the Outlook window message.

If nothing helps, well, the options remaining are to repair the Office program or create a new User profile and see. 

Posted by on , in Category Office with Tags
Anand Khanse is the Admin of TheWindowsClub.com, a 10-year Microsoft MVP Awardee in Windows (2006-16) & a Windows Insider MVP. Please read the entire post & the comments first, create a System Restore Point before making any changes to your system & be careful about any 3rd-party offers while installing freeware.


  1. Alberto Gorin

    mi computer windows 10 so now and than freez up
    i have livemail also freez up than all computer freez up
    removed some USB device checked hard drive for errors its solved
    i think its westeren digital mechinical hard drive

  2. IT

    Nope. Does it on SSDs (Toshiba), too.

  3. Steve Jhonsan

    Customer Care for Outlook 1800-585-2494

  4. Stella

    Outlook Service 18OO(585)2494

  5. OutIook HeIp18OO 585 2494

    If outlook is not working

  6. Rozeritta

    Need assistance caII now outIook 18OO 585 2494

  7. kentek3141

    Anand, you are the GREATEST! I have 5 hours working on clients Surface Pro3/win 10 Outlook. I removed all the .nst and .ost files, let OL reload and it worked. Then, do a reboot and it fails. Your Graphic Acceleration fixed it. Surface Pro 3 has hardware bugs that have not been fixed.

  8. Mohamad Issa

    I had the same problem, even outlook won’t start in safe mood , I been trying for ages to fix it but I managed to resolve this issue with these steps
    1- Open control panel
    2- type mail on the search bar
    3- click on mail
    4- click on mail accounts
    5- delete your mail account completely.
    6- click on new and create your mail account again.
    Job done, good luck

  9. Suzzane

    You may contact 0utlook Care at 18OO 585 2494

  10. Cari Morrison

    After trying every thing suggested, I finally tried this – and so far it appears to have worked! See my happy face!

  11. InMyMindsAyn

    We had this problem where I work. Roboforms was running in the background (it was an older version). As soon as it was closed Outlook worked just fine.

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