Microsoft 365 Enterprise Outlook won't launch

Question

For the past few weeks, I have not been able to open my outlook 365 business account. Has anyone encountered this issue?

Answer 1

Hi Eulanda Riddick

Since you’re using Classic Outlook for Microsoft 365 Business, please try the following troubleshooting steps:

1, Repair Microsoft 365 (Online Repair)

• Go to Windows Settings > Apps > Installed apps > Microsoft 365 > Modify, then select Online Repair and follow the prompts.
• Alternatively, you can do this via Control Panel > Programs and Features, right‑click Microsoft 365 Apps for Enterprise, select Change, and choose Online Repair.

2, Start Outlook in Safe Mode

• Press Win + R, type outlook.exe /safe, and press Enter.

3, Create a new Outlook profile

• Close Outlook, then refer to this article for detailed steps: Create an Outlook profile. Set it as the default and try launching Outlook again.

4, Use Outlook on the web temporarily

• While troubleshooting, you can access your mailbox at https://outlook.office.com to confirm the mailbox itself is working.

If this issue started after a recent Windows or Office update, it may also be related to a known issue affecting Classic Outlook. In that case, ensuring Office and Windows are fully up to date can help.

To better understand the behavior, do you see any error message when launching Outlook, or does the window simply fail to open or close immediately?

Please let me know how you get on, as your feedback is valuable to the community.

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