Safe mode starts Windows in a basic state, using a limited set of files and drivers. If a problem doesn't happen in safe mode, this means that default settings and basic device drivers aren't causing the issue.

See how to work with Office safe modes to safely use a Office program that has encountered certain problems.

Type Outlook.exe /safe, and click OK. Tip: If Windows can't find Outlook.exe /safe, try using the full path to Outlook (for example C:\Program Files\Microsoft Office\OfficeXX, where XX is your version number).

Start your PC in safe mode. If you're having trouble restarting, you can start your PC in safe mode. See Start your PC in safe mode in Windows 10 for details. From safe mode, you can try the remaining troubleshooting steps. Check the Device Manager. Right-click the Start button and select Device Manager.

Start Outlook in safe mode and disable add-ins How do you know you're working in safe mode? You'll see a label similar to the one below at the top of the screen. The Outlook icon on your taskbar includes an exclamation symbol to alert you the program isn't operating normally.

Learn about the recovery options in Windows. Find out how to reset your PC, go back to a previous version of Windows, or use media to reinstall Windows.

This is similar to starting Windows in Safe Mode, but provides you more control over which services and programs run at startup to help you isolate the cause of a problem.

Describes how to use the System File Checker tool to troubleshoot missing or corrupted system files in Windows.

To change these settings, you will need to switch the PC boot mode from one enabled as “Legacy” BIOS (also known as “CSM” Mode) to UEFI/BIOS (Unified Extensible Firmware Interface).

Starting your device in Safe Mode can help troubleshoot sign-in problems. If you can sign in using Safe Mode, it means that basic device drivers and default settings weren’t causing the sign-in problem.