Outlook not opening in Windows 11: fixes for new and classic Outlook

When Outlook is not opening in Windows 11, it usually either does nothing when you click it, shows a “Cannot start Microsoft Outlook” message, or hangs on the “Loading profile” screen. The fix depends on which Outlook you use, so start by working that out, then go through the steps for your version from the top. Most problems are solved within the first three steps.

This is an independent guide and freetechsupport.org is not affiliated with Microsoft. For work or school accounts, your organisation’s IT team may manage Outlook and should be your first contact.

Which Outlook do you have?

• New Outlook for Windows looks like Outlook on the web and appears in the Start menu as Outlook (new) or just Outlook. It comes with Windows 11 or from the Microsoft Store.
• Classic Outlook is the traditional desktop program with a File tab and a ribbon. It is installed with Microsoft 365 or Office.

Microsoft lets you move between them with the Try the new Outlook toggle at the top right. If the new app will not open, you can still start classic Outlook from the Start menu if it is installed.

Step 1: end a stuck copy of Outlook (both versions)

Outlook sometimes keeps running invisibly after a crash, and a second copy refuses to start.

1. Right-click Start and choose Task Manager.
2. Look for Microsoft Outlook or Outlook (new) under Processes.
3. Select it and choose End task.
4. Start Outlook again.

If that does not help, restart the PC. A pending Windows or Office update can also block Outlook until the restart completes.

Step 2: start classic Outlook in safe mode

Safe mode starts classic Outlook without add-ins and custom toolbar settings.

1. Close Outlook.
2. Press Windows key + R, type outlook.exe /safe and press Enter. Alternatively, hold Ctrl while clicking the Outlook shortcut and confirm.
3. Choose your profile if asked.

If Outlook opens in safe mode, an add-in is the likely cause:

1. Go to File > Options > Add-ins.
2. Next to Manage, choose COM Add-ins and select Go.
3. Clear the check boxes for all add-ins and select OK.
4. Restart Outlook normally. If it opens, turn add-ins back on one at a time to find the faulty one, then update or remove it.

If Outlook does not open even in safe mode, go on to step 3.

Step 3: repair Office (classic Outlook)

1. Open Settings > Apps > Installed apps.
2. Find Microsoft 365 or Microsoft Office, select the three dots and choose Modify.
3. Choose Quick Repair first. If the problem continues, run Online Repair, which takes longer and needs an internet connection.

Step 4: reset the navigation pane (classic Outlook)

A damaged navigation pane settings file can stop Outlook at start-up. Press Windows key + R, type outlook.exe /resetnavpane and press Enter. This resets the folder pane layout only; it does not delete mail.

Step 5: repair the data file or create a new profile (classic Outlook)

If Outlook hangs on Loading profile, the profile or data file may be damaged.

• Repair a .pst or .ost file. Close Outlook and run the Inbox Repair Tool, SCANPST.EXE, from your Office installation folder (for Microsoft 365 it is usually under C:\Program Files\Microsoft Office\root\Office16). Point it at the data file and select Start, then Repair. For server-based accounts, deleting a damaged .ost file is also safe because it rebuilds from the server, but back up any .pst files first.
• Create a new profile. Open Control Panel > Mail > Show Profiles, choose Add, set up your account again, then select Always use this profile and pick the new one. Your old profile stays in place, so you can switch back.

Fixes for the new Outlook for Windows

The new Outlook has fewer settings to repair, so the main steps are:

1. End the task in Task Manager as in step 1, then start it again.
2. Check for updates in the Microsoft Store under Library, and install Windows updates from Settings > Windows Update.
3. Uninstall and reinstall. Microsoft’s guidance is to uninstall the new Outlook from the Start menu (right-click it or use the list option, then Uninstall) and reinstall it from the Microsoft Store. Sign in again; mail for server-based accounts syncs back.
4. Check Microsoft’s known issues page for new Outlook, which lists current problems and workarounds.
5. Use classic Outlook or Outlook on the web meanwhile at outlook.com or outlook.office.com so you can keep working.

If none of this works

• Try signing in to Outlook on the web. If it works there, your account is fine and the problem is the app on this PC.
• Create a new Windows user account and try Outlook there. If it works, the problem is in your Windows profile.
• For Microsoft 365 business accounts, contact your administrator; licence or policy problems can stop Outlook from opening.

Avoid fake Outlook support

Search ads sometimes show “Outlook support” phone numbers that are not Microsoft. Microsoft does not need remote access to your PC to fix Outlook start-up problems. Read spot and stop fake tech support calls if someone contacts you first.

Related guides

Outlook not receiving emails, Outlook keeps asking for a password, Outlook disconnected or working offline and email stuck in the Outbox.