Outlook is crashing when synchronizing inbox

Question

My Outlook with Office 365 on my Dell laptop keeps crashing when folders are being synchronized. When I restart, it tries to download (synch?) 500 or so emails and then crashes again.

Answer 1

If Outlook is crashing during synchronization, particularly when dealing with a large number of emails, there are a few steps you can take to troubleshoot the issue:

1. Investigate Add-ins: Sometimes, add-ins can cause Outlook to crash. You can start Outlook in Safe Mode by running Outlook /safe from the Run dialog (Windows key + R). If the crashing stops, you can disable add-ins one by one to identify the culprit.
2. Repair Office: You can try repairing your Office installation. Go to Control Panel, select "Uninstall a program," find your Office installation, right-click it, and choose "Change" followed by "Online Repair."
3. Create a New Outlook Profile: If the issue persists, creating a new Outlook profile may help. Open Control Panel, click on "Mail," then "Show Profiles," and add a new profile. This can resolve issues related to corrupted profiles.
4. Reduce the Number of Folders: If you are using a shared mailbox, consider reducing the number of folders in the shared mailbox. Outlook has a limitation on the number of shared folders it can handle efficiently, and reducing them can improve performance.
5. Run Diagnostics: Use the Microsoft Support and Recovery Assistant (SaRA) to run diagnostics and fix issues related to Outlook connectivity.

By following these steps, you should be able to resolve the crashing issue during synchronization.

---

References:

• How to troubleshoot issues that cause Outlook to crash or stop responding when used with Microsoft 365
• How to troubleshoot issues that cause Outlook to crash or stop responding when used with Microsoft 365

Answer 2

Thanks for the update Jeff.

Answer 3

Tech Support said the culprit is the latest MS Security Update. A new one is apparently to be released next week.

Answer 4

This behavior is often caused by a corrupted Outlook profile, a problematic add-in, or a damaged local data file OST. A good first step is to start Outlook in Safe Mode to see if an add-in is causing the crash. If it works there, disabling add-ins usually resolves the issue. You can also try creating a new Outlook profile, which often fixes repeated sync crashes because it rebuilds the mailbox connection cleanly. Microsoft also recommends repairing Office if the crashes continue. https://support.microsoft.com/en-us/office/outlook-crashes-or-stops-responding-when-used-with-office-365-bd61bbce-36a5-44d8-a521-9440e5418337.

Start Outlook in Safe Mode, https://support.microsoft.com/en-us/office/open-outlook-in-safe-mode-f394c2ee-b2af-e97a-64ee-35cd24414811.

Create a new Outlook profile, https://support.microsoft.com/en-us/office/create-an-outlook-profile-f544c1ba-3352-4b3b-be0b-8d42a540459d.

Repair Microsoft Office, https://support.microsoft.com/en-us/office/repair-an-office-application-7821d4b6-7c1d-4205-aa0e-a6b40c5bb88b.

If the issue persists, it would help to know whether Outlook crashes in Safe Mode, whether this is an Exchange or IMAP account, and if the problem started after a recent update or large mailbox sync.