Why Is Microsoft Outlook Not Working? How to Fix?

Microsoft Outlook is obviously one of the most complex and advanced email client. It has superior flexibility for the users by serving as a great connectivity tool. But professional add-ins in Outlook is not working and cause improper functioning. Outlook usually archives the Inbox emails to reduce the size of its mailbox. However, it increases when more and more items are added.

Like several other Office programs from Microsoft, Outlook has risk to crash and stop responding or working for some reasons when it comes to send an email or open a file. Users have faced such an experience on all the widely used versions of Outlook like 2010, 2007, 2013, and 2016. Hence, Outlook finds hard to provide seamless access to mailboxes and eventually cause an error “Not Responding”. Antivirus programs also have advanced security settings which keep Outlook from working properly. If your Outlook has stopped working, keep reading this post.

Why Is Microsoft Outlook Not Working

Wait for a while

Sometimes, Outlook is used by several processes when it is stopped or stuck, for example, while moving a bulk of messages or deleting them at once. Usually, this problem is fixed automatically after a few minutes.

Run Outlook in Safe Mode

To run Outlook without add-ins in Safe Mode, open Run from WinX menu, type outlook/safe and press Enter button. If you couldn’t get any problem in Outlook, there are chances that its add-in is causing trouble. See your installed add-ins in Outlook and disable them one by one to find the one which is causing problem.

Disable Graphics Accelerator

Try to disable hardware graphics acceleration to see if it works. Hardware Acceleration uses hardware of your system to perform a certain task and to work faster than the software itself. But it causes conflict in some systems. Turn it off to see if you are still getting the error “Outlook not Responding”. Keep in mind that it is disabled for all Office programs once you disable it for Outlook.

To do this, simply go to File > Options > Mail > Compose Messages > Editor Options button > Advanced.

In Display section, select the option “Disable hardware graphics acceleration” and click Apply/Ok. Restart your Outlook and see if the error goes away. There are chances that video driver is causing problem. Update it and see if it works.

Kill the Processes of Outlook.exe

If multiple processes are using Outlook, you are able to kill it to stop Outlook hanging. Follow these steps to do it –

  • Start Windows Task Manager. Either right click the taskbar or press “Ctrl+Alt+Del”
  • Click on Start Task Manager and switch to Processes tab.
  • Click on OUTLOOK.EXE and press “End Process” button.

Close all the Applications and Programs opened

Outlook is a very complex application. So, it needs a lot of CPU usage. Along with it, Outlook doesn’t have the memory required to perform a specific operation. So, it can eventually cause the error “Outlook not Responding” The key here is to close all the other programs which are not important yet.

Disable Antivirus

Sometimes outdated Antivirus may be the reason behind Outlook errors. Antivirus often conflicts with Outlook and keeps them from working well. So, it is always advised to update antivirus on timely basis. Along with it, be sure that add-ins is added to the list of trusted applications of your Antivirus.


We hope these above methods will help you fix the “Outlook Not Responding” error. If none of these steps worked, there are chances that Outlook data file might be corrupt. Here, you need to use a reliable PST repair tool to resolve the error.