Outlook will not open at all

Create a new Outlook profile from the Windows Run dialog; because Outlook also fails in Safe Mode, disabling add-ins inside Outlook is not currently an available path.

1. Test with a new Outlook profile

A damaged Outlook profile can prevent startup. Creating a new profile does not delete the existing one.

1. Press Windows key + R.
2. Enter:

      Outlook.exe /profiles
   

3. Select Options.
4. Select New.
5. Give the profile a name, select OK, and add your email account.
6. Select the new profile and start Outlook.

Microsoft documents /profiles specifically as an alternative way to open the profile picker.^1^

• If Outlook opens: continue using the new profile. The original profile is likely damaged.
• If the profile picker does not open, or the new profile also fails: proceed to Office repair.

2. Repair Microsoft 365 or Office

Since restarting and Safe Mode did not help, repair the installed Office files:

Windows 11

1. Right-click Start → Installed apps.
2. Find Microsoft 365 or Microsoft Office.
3. Select … → Modify.
4. Run Quick Repair first.
5. If Outlook still does not open, return to the same screen and run Online Repair.

Windows 10

1. Right-click Start → Apps and Features.
2. Select Microsoft 365 or Microsoft Office → Modify.
3. Run Quick Repair, followed by Online Repair if necessary.

Online Repair is more comprehensive and repairs the entire Office suite, not only Outlook.^2^

3. If this started recently on Microsoft 365

There is a documented March 2026 issue in which older classic Outlook builds can crash when used with a newer Teams Meeting Add-in. This applies only to Outlook for Microsoft 365 with the affected older builds; do not assume it applies to perpetual editions such as Outlook 2021 or 2024.

Because Outlook will not open, update Office from another Office application:

1. Open Word.
2. Select File → Account.
3. Select Update Options → Update Now.
4. After updating finishes, try Outlook again.

Microsoft’s immediate resolution for that specific issue is updating classic Outlook to the latest build; Online Repair is the documented workaround.^3^

4. If Outlook still cannot start

Repairing the Outlook data file is the next conditional step, particularly for accounts using a local .pst file. Microsoft’s Inbox Repair Tool, scanpst.exe, scans Outlook data files for errors.^4^

Do not delete the existing profile or .pst file while troubleshooting. If a new profile and Online Repair both fail, note any exact error message and check Event Viewer → Windows Logs → Application for an OUTLOOK.EXE crash entry; the faulting module and exception code will help distinguish an Office installation crash from a profile or data-file problem.

References

1. Create a profile in classic Outlook for Windows
2. Repair an Office application
3. Classic Outlook crashes and opens in Safe Mode starting March 12 2026 | Microsoft Support
4. [Classic Outlook](https://support.microsoft.com/outlook/getstarted/outlook-for-windows-not-responding-hangs-freezes-or-stops-working)