UTC Date: 2026-01-30T13:08:08.153Z Client Id: CA66653D0C1847EE91E0229FB256659C Session Id: 029a0fc7-5308-4e01-9ce9-696106bcbe75 Client Version: 20260116004.05 BootResult: throttle Back Filled Errors: Unhandled Rejection: Error: 500:undefined|undefined:und

The error message you are encountering, TooManyObjectsOpenedException, indicates that your session has exceeded the limit of opened objects in Outlook. This can happen if there are too many items open in your session, which can lead to performance issues and errors like the one you are seeing.

To resolve this issue, you can try the following steps:

1. Close Unused Items: Make sure to close any unnecessary emails, calendar items, or other objects that you have opened in your Outlook session.
2. Restart Outlook: Sometimes, simply restarting Outlook can help clear the session and reset the limits.
3. Check for Updates: Ensure that your Outlook client is up to date, as updates may contain fixes for such issues.
4. Limit Concurrent Sessions: If you are working with multiple accounts or sessions, try to limit the number of concurrent sessions you have open.
5. Contact Support: If the issue persists, consider reaching out to your IT support or Microsoft support for further assistance, as they may need to check server-side settings or logs.

By following these steps, you should be able to manage the session limits and resolve the error you are encountering.

Dear AReid ,

Thank you for reaching out to the Microsoft Q&A forum. 

Based on the information you provided, it appears that you are unable to access Outlook and are encountering the TooManyObjectsOpenedError after signing in. 

This issue typically occurs when an Outlook mailbox reaches a limit on how many internal objects it can have open simultaneously. These “objects” include not only emails, but also drafts, calendar entries, contacts, and other background components used by the mailbox. 

To help us better identify the cause, could you please confirm whether you are using a personal account or a business/work account when the error appears? 

In the meantime, please try the following steps: 

Sign out of all Outlook session from both Outlook desktop and Outlook web

• For personal account: please access to https://go.microsoft.com/fwlink/?linkid=2253707

• For business account: please access to My Sign-Ins | Security Info | Microsoft.com

It may take up to 24 hours to take effect, please help me to try every 6 hours to see if you are able to access Outlook normally. 

Clear cache of the Edge browser: Clear browsing history

Clear cache of Outlook desktop:

• Close Outlook completely and press Windows + R to open the Run dialog. 
• Type %localappdata% and press Enter. 

Open Outlook in safe mode (for Outlook desktop): Press Win + R, type:  outlook /safe

Please feel free to let me know if there is any update after you have tried and wait for 24 hours. I am looking forward to hearing from you.  

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