Quick summary: Classic Outlook for Windows won't open, keeps saying "Trying to connect", or emails are stuck in the Outbox? Work through these 9 fixes in order, from the quickest checks to a full repair. Most problems are solved in the first five steps, and none of them deletes your email.
Before you start: is it you or Microsoft?
If Outlook suddenly stops working for you and your colleagues at the same time, the problem may be on Microsoft's side. Check the Microsoft 365 Service Status page, the @MSFT365Status account on X, or ask your IT admin to look at Service Health in the admin center. During the November 12, 2026 Microsoft 365 outage, for example, no local fix could help. If the service is healthy, continue below.
Fix 1: Check Work Offline and your internet
Open the Send / Receive tab and make sure Work Offline is not highlighted. Then open any website in your browser to confirm your internet connection works. Restart your router if needed.
Fix 2: Restart Outlook completely
Close Outlook, then open Task Manager (Ctrl+Shift+Esc) and end any remaining OUTLOOK.EXE process. Open Outlook again. A full restart also helps after Windows or Office updates.
Fix 3: Try Outlook on the web
Sign in at outlook.office.com (work/school) or outlook.com (personal). If your email works there, your account is fine and the problem is inside the desktop app on your PC.
Fix 4: Start Outlook in Safe Mode
Safe Mode starts Outlook without add-ins. Hold Ctrl while clicking the Outlook icon and choose Yes, or press Win+R, type outlook.exe /safe and press Enter. If Outlook works in Safe Mode, an add-in is the likely cause.
Fix 5: Disable problem add-ins
Go to File > Options > Add-ins, choose COM Add-ins and click Go. Untick all add-ins, restart Outlook, then turn them back on one at a time to find the faulty one. Microsoft notes that an outdated version of some add-ins (for example ABBYY FineReader) can stop Outlook from starting.
Fix 6: Repair your email account
Go to File > Account Settings > Account Settings, select the email account and click Repair. Follow the steps and restart Outlook. This lets Outlook detect and fix errors in the account configuration.
Fix 7: Reset the navigation pane
If Outlook shows "Cannot open the Outlook window", press Win+R, type Outlook.exe /resetnavpane and press Enter. This resets the folder pane, which can be corrupted.
Fix 8: Create a new Outlook profile
A damaged profile is a common cause of "Trying to connect" and loading problems. Open Control Panel > Mail (Microsoft Outlook) > Show Profiles > Add, create a new profile with your email account, then choose Prompt for a profile to be used and start Outlook with the new profile. Your Microsoft 365 / Exchange email is stored on the server, so it downloads again automatically.
Fix 9: Repair Office and data files
- Repair Office: open Settings > Apps > Installed apps, find Microsoft 365 or Office, choose Modify, then run Quick Repair. If that does not help, run Online Repair.
- Repair a PST file: if you use a local .pst file (for example POP email or archives), run the Inbox Repair Tool (
SCANPST.EXE) to scan and fix it. - Guided troubleshooter: Microsoft's Get Help troubleshooter for classic Outlook can diagnose many startup and connection problems automatically.
Still not working?
- Check your Outlook version. Microsoft says support for Office 2016 and 2019 clients connecting to Microsoft 365 services has ended, so very old versions can stop connecting.
- Check your password and MFA. A recent password change can leave Outlook stuck asking for credentials.
- Contact your IT admin for work accounts; they can see server-side logs.
- Beware fake support. Never call numbers from pop-ups; read our guide on spotting fake Microsoft support scams.
FAQ
Will creating a new profile delete my emails?
For Microsoft 365, Exchange and Outlook.com accounts, no, because email is stored on the server. Back up any local .pst files before removing old profiles.
Why does Outlook work in Safe Mode only?
Usually because an add-in is causing the problem. Disable add-ins one by one to find it.
What does "Trying to connect" mean?
Outlook cannot reach the mail server. Check service status, internet, Work Offline, then repair the account or create a new profile.
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