Outlook Keep crashing

Question

Outlook Keep crashing

Robin McFarlane 5

Outlook crashes after completing one action or about 5 minutes. When I restart the program the changes I made before it crashes revert (massages become unread and back in my inbox, messages not sent, messages not deleted etc.).
This has happened over and over the last 2 hours.

Ruby-N 11,405 Reputation points Microsoft External Staff Moderator

2026-01-19T16:21:01.3166667+00:00

Good day @Robin McFarlane,

I hope everything is going well on your end.

I’m following up on the support thread we've been working through together. I wanted to check in and see if the information I shared in my previous answer helped clarify the issue you were experiencing.

If you're still experiencing any issues or have further questions, please feel free to reach out at any time. I’m always happy to help if you need anything else.

We want to ensure that everything is functioning smoothly and that your experience remains seamless.

Thank you again for your collaboration throughout the troubleshooting process.

I look forward to hearing from you soon.
Robin McFarlane 5 Reputation points

2026-01-19T16:37:31.22+00:00

No, none of the solutions worked. We found that we were experiencing the same problem as others:

https://learn.microsoft.com/en-us/answers/questions/5721083/outlook-freezing-and-not-responding-and-not-saving

We reverted the updates until it was back to a place where outlook was working again. I still don’t have the emails I did manage to send in between crashes in my sent folder. Even though I have responses from those emails.

Thank you.
Robin McFarlane 5 Reputation points

2026-01-19T20:50:57.2933333+00:00

The security update we removed was reinstalled and the problem returned. We paused updates.
Ruby-N 11,405 Reputation points Microsoft External Staff Moderator

2026-01-19T23:31:44.57+00:00
Dear @Robin McFarlane,

Thank you again for reaching out and for keeping me updated on your situation. I appreciate the detailed update and it is important to note that the issue reoccurred following the reinstallation of the security update.

Since the issue continues even after reverting and reinstalling the update, the best next step is to have Microsoft Support take a closer look. Their engineering team can review system-level logs and backend data that are not accessible from mine side, which will help identify what’s causing the recurring behavior.

I sincerely recommend reaching out to your IT administrator to create a support ticket via Microsoft 365 Admin Center > Support > Help & Support for further investigation.

Thank you again for your patience and understanding regarding the limitations on my side.
Julian Rosales 5 Reputation points

2026-01-20T19:25:57.24+00:00

Had the same problem and got it solved with the help of ChatGPT which recommended amongst other things to check if the outlook PST file was in cloud folder (onedrive or Dropbox).

Solution came from disabling OneDrive and moving the pst file to a non cloud folder. To to this you need to copy the pst file without deleting the old one into a new folder. Once this is done you can change the pst file in outlook / account settings.

3 answers

Your answer

Ruby-N 11,405 Reputation points Microsoft External Staff Moderator

2026-01-19T16:21:01.3166667+00:00

Good day @Robin McFarlane,

I hope everything is going well on your end.

I’m following up on the support thread we've been working through together. I wanted to check in and see if the information I shared in my previous answer helped clarify the issue you were experiencing.

If you're still experiencing any issues or have further questions, please feel free to reach out at any time. I’m always happy to help if you need anything else.

We want to ensure that everything is functioning smoothly and that your experience remains seamless.

Thank you again for your collaboration throughout the troubleshooting process.

I look forward to hearing from you soon.
Robin McFarlane 5 Reputation points

2026-01-19T16:37:31.22+00:00

No, none of the solutions worked. We found that we were experiencing the same problem as others:

https://learn.microsoft.com/en-us/answers/questions/5721083/outlook-freezing-and-not-responding-and-not-saving

We reverted the updates until it was back to a place where outlook was working again. I still don’t have the emails I did manage to send in between crashes in my sent folder. Even though I have responses from those emails.

Thank you.
Robin McFarlane 5 Reputation points

2026-01-19T20:50:57.2933333+00:00

The security update we removed was reinstalled and the problem returned. We paused updates.
Ruby-N 11,405 Reputation points Microsoft External Staff Moderator

2026-01-19T23:31:44.57+00:00

Dear @Robin McFarlane,

Thank you again for reaching out and for keeping me updated on your situation. I appreciate the detailed update and it is important to note that the issue reoccurred following the reinstallation of the security update.

Since the issue continues even after reverting and reinstalling the update, the best next step is to have Microsoft Support take a closer look. Their engineering team can review system-level logs and backend data that are not accessible from mine side, which will help identify what’s causing the recurring behavior.

I sincerely recommend reaching out to your IT administrator to create a support ticket via Microsoft 365 Admin Center > Support > Help & Support for further investigation.

Thank you again for your patience and understanding regarding the limitations on my side.
Julian Rosales 5 Reputation points

2026-01-20T19:25:57.24+00:00

Had the same problem and got it solved with the help of ChatGPT which recommended amongst other things to check if the outlook PST file was in cloud folder (onedrive or Dropbox).

Solution came from disabling OneDrive and moving the pst file to a non cloud folder. To to this you need to copy the pst file without deleting the old one into a new folder. Once this is done you can change the pst file in outlook / account settings.

Answer 1

Dear @Julian Rosales,

Thank you so much for sharing this valuable information with us. I truly appreciate you taking the time to let us know what worked on your side.

I am glad to hear that you were able to resolve the issue by disabling OneDrive and moving the Outlook PST file to a non‑cloud folder. Your detailed explanation about copying the PST file to a new location and updating it in Outlook’s account settings is extremely helpful. Insights like yours not only help us better understand your experience but can also assist other users facing similar challenges.

Thank you for your kindness and contributions to the forum.

Dear @Robin McFarlane,

At the moment, the investigation is still ongoing. However, the engineering team has shared several temporary workarounds that may help improve the situation while a permanent fix is being developed. You can review the detailed guidance here: Classic Outlook profiles with POP accounts and PSTs hang after Windows updates on January 13, 2026 …

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If you have already tried these steps and the issue continues, please rest assured that the Windows team is actively working on a resolution as quickly as possible. I know how important a stable Outlook experience is, and resolving this remains a priority.

I hope this issue is resolved soon. I'm glad to assist and truly hope the information provided has been useful. Please feel free to reach out anytime if you need further assistance.

If you find my post helpful, kindly consider marking it as the accepted answer. Doing so can assist others in the community who may have similar questions in finding solutions more quickly.

I genuinely appreciate your patience and understanding throughout this process.

Answer 2

Dear @Robin McFarlane,

Thank you for posting your question in the Microsoft Q&A forum.

I understand how inconvenient it is when Outlook crashes frequently and reverts your changes. This issue typically points to one of two causes:

An unstable add-in.
A corrupted local Outlook cache or profile.

Please see the following workarounds that will help you verify and better understand the issue:

Make sure both your operating system and Classic Outlook app are fully updated.

Option 1: Start Outlook in safe mode & disable add‑ins

Press Windows + R.

Type outlook.exe /safe.

If Outlook stays stable in Safe Mode, go to File > Options > Add‑ins > Manage: COM Add‑ins > Go, uncheck everything, OK, then restart Outlook normally. Re‑enable add‑ins one by one to find the offender.

Option 2: Clear the Classic Outlook cache

Corrupted or outdated cache files can also generate repeated login requests. Here's how to clear the Outlook cache:

Close Outlook completely.

Press Windows + R to open the Run window.

Enter this path and press Enter:

%localappdata%\Microsoft\Outlook\RoamCache

When the folder opens, press Ctrl + A to select all the files and delete them.

Restart Outlook. It will automatically rebuild these files.

This helps remove outdated stored data that may interfere with normal Outlook syncing.

Option 3: Recreate Outlook profile

Close Outlook.

Go to Control Panel > Search for “Mail” and select it > Show Profiles.

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Create a new profile and set it as default.

Restart Outlook and sign in again.

Option 4: Repair Outlook app

This article provides further guidance on the topic: Repair an Office application - Microsoft Support

Option 5: Reinstall Office

Please uninstall all office apps. Then sign in at office.com > Apps > Install apps > Microsoft 365 apps > Apps & devices > Install Office.

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As community moderators, we kindly ask for your understanding that our access to internal development details is limited. Our primary role is to guide users toward the appropriate resources and support channels. While we may not have visibility into performing deeper backend analysis, we’ll continue doing our best to support you within the scope of our responsibilities.

I hope this information is helpful. If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.

Thank you for your patience and understanding.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have any extra questions about this answer, please click "Comment".

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Answer 3

If Outlook is crashing frequently and reverting changes, there are several troubleshooting steps you can take to resolve the issue:

Investigate Possible Issues Caused by Add-ins: Start Outlook in safe mode by using the command Outlook /safe. If the issue does not occur in safe mode, it may be caused by an add-in. You can disable add-ins by going to Options > Add-Ins and unchecking them.
Repair Office: You can repair your Office installation by going to Control Panel > Uninstall a program, right-clicking on your Office installation, and selecting Change, then Online Repair.
Run Outlook Diagnostics: Use the Classic Outlook Connectivity troubleshooter to identify and fix issues. Make sure you are using the same Windows device that classic Outlook is installed on.
Create a New Outlook Profile: If the problem persists, consider creating a new Outlook profile. Go to Control Panel > Mail > Show Profiles, and then add a new profile.
Check for Updates: Ensure that your Office applications are up to date, as updates can fix bugs and improve stability.
Repair Outlook Data Files: Use the Inbox repair tool (scanpst.exe) to repair any corrupted Outlook data files. This tool can be found in the installation directory of Outlook.

By following these steps, you should be able to address the crashing issue with Outlook and prevent data loss from unsaved changes.

References:

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Outlook Keep crashing

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