Why does by Outlook icon open to a box showing session id and error code?

Question

When I click on the Outlook icon on my pc a box pops up showing the following:

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Session Id: <Information deleted for privacy protection>

Timestamp: <Information deleted for privacy protection>

Error code: CANCEL

Outlook was working on Wednesday 10/29/25 but not Thursday 10/30/25 at 1 pm. Never had this issue before and not sure what to do.

Answer 1

Dear @Janice B, 

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

I understand how inconvenient it must be to encounter this unexpected error. This typically indicates that Outlook failed to launch or connect properly, possibly due to a corrupted profile, interrupted update, or connectivity issue. 

In the meantime, you can refer to some workarounds to verify the issue:     

Make sure your operating system is updated to the latest versions. Keeping your software current not only enhances performance and stability but also ensures compatibility with new features and helps protect against security vulnerabilities.   

Option 1: Check via Outlook web  

Go to https://office.com and sign in with your account.   

Navigate to Apps > Outlook.   

 

This will redirect you to Outlook on the web, where you can sign in to help verify the issue. 

As a temporary workaround, you can use Outlook on the web to continue accessing your emails while we work on verifying the issue. 

Option 2: Open Outlook safe mode  

You may try open Outlook in safe mode to check if one of your add-ins might be interfering.  

Option 3: Repair Outlook app  

Repair the Outlook app to fix any corrupted files or configuration issues that might be causing the problem.   

Note:   

If you proceed with this step, all app settings and saved login information will be reset. This means you may need to reconfigure your preferences and sign in again after the reset.    

We recommend backing up any important settings or data beforehand, if possible.   

You can find this article helpful for further details: Repair an Office application - Microsoft Support  

Option 4: Reinstall the Outlook app 

You can choose to either uninstall all Office apps or just remove the Outlook app and reinstall it via office.com, depending on your preference. This ensures you get the latest version and a clean installation.  

Please sign in to your account at office.com to proceed. Then navigate to Apps > Install Apps > Microsoft 365 apps > Click on Apps & devices > Install Office.      

Note: Please make sure you're signed in with an account that has an active license for Office apps.  

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 the information provided proves useful. Please proceed with the outlined steps and let me know whether they resolve the issue. If not, I’ll be glad to continue working with you to find a solution.  

Thank you for your patience and understanding throughout this process. Should you have any questions or need further assistance, feel free to reach out at any time.  

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