How to fix non moving emails and unresponsive apps.

Check Microsoft 365 admin center → Health → Service health first, because Outlook, OneDrive, and Copilot becoming unresponsive at the same time is best treated as a possible tenant/service incident before repairing individual Windows apps.^1^

1. Check for a Microsoft 365 incident

An administrator—or someone with the Service Support or Helpdesk admin role—should:

1. Sign in to the Microsoft 365 admin center.
2. Open Health → Service health.
3. Review:
   • Exchange Online for delayed or missing email.
   • Microsoft 365 Copilot.
   • OneDrive for Business/SharePoint Online.
4. Open any active incident and review User impact, Status, and the latest update.

There is currently a reported Microsoft 365 Copilot issue that can prevent Copilot Chat from loading or accessing work data. The public consumer status reports Outlook.com and OneDrive as operational, but that does not represent your organization’s tenant-specific Exchange Online or OneDrive health.^2^

If Exchange Online or OneDrive shows an active incident matching your symptoms, monitor that incident rather than reinstalling or reconfiguring the apps. Microsoft posts investigation and restoration updates on the service-health page.^1^

2. Separate a cloud problem from a Windows app problem

Test from a browser and, if possible, from another network or device:

• Open Outlook on the web and check whether new messages appear.
• Open OneDrive on the web and try listing or opening a file.
• Open Microsoft 365 Copilot on the web.

Interpret the result as follows:

• Web and desktop both fail for several users: continue with the tenant/admin checks below.
• Web fails for only one user: check that user’s Exchange Online license and mailbox.
• Web works but the Windows apps do not: skip to the local Windows section.

Microsoft specifically recommends Outlook on the web as the test for distinguishing an Exchange/mailbox problem from an installed Outlook problem.^3^

3. If email also fails on the web

A Microsoft 365 administrator should:

1. In the admin center, open Users → Active users → affected user.
2. Confirm that the account still has an applicable license containing Exchange Online.
3. Run Diag: Troubleshoot Email Delivery in the admin center, entering a known sender, recipient, and approximate sending time. This diagnostic requires an administrator account and is unavailable in certain sovereign Microsoft 365 environments.^3^
4. Open Exchange admin center → Mail flow → Message trace.
5. Search using the affected recipient and today’s time range:
   • Delivered means Exchange accepted delivery; investigate mailbox rules, filtering, or the client.
   • A failed or blocked result should include details and a How to fix it action.
   • No trace may indicate the message never reached your Microsoft 365 organization.

If the issue is absent from Service health but affects multiple users, select Report an issue on the Service health page. If diagnostics do not identify the problem, create a support request from the Microsoft 365 admin center.^1^

4. If the web services work but Windows apps remain unresponsive

For classic Outlook:

1. Close Outlook.
2. Press Windows+R, enter outlook.exe /safe, and select OK.
3. If Outlook works in safe mode, open File → Options → Add-ins.
4. Beside Manage: COM Add-ins, select Go, disable the add-ins, and restart Outlook normally.
5. Re-enable add-ins individually to identify the failing one.

If Outlook still hangs, close all Microsoft 365 apps, then open:

Control Panel → Programs and Features → Microsoft 365 → Change → Online Repair

Safe-mode/add-in testing and Online Repair are documented for classic Outlook; they do not apply to new Outlook in the same way.^4^

Avoid deleting the existing Outlook profile initially. Removing it can also remove associated local data files; create a separate test profile instead if repair does not help.

References

1. How to check Microsoft 365 service health
2. status.cloud.microsoft
3. Find and fix email delivery issues as a Microsoft 365 for business admin
4. Outlook crashes or stops responding when used with Office 365 | Microsoft Support