If some Windows functions aren't working or Windows crashes, use the System File Checker to scan Windows and restore your files. Though the steps below might look complicated at first glance, just follow them in order, step-by-step, and we’ll try to get you back on track.

The Program Install and Uninstall troubleshooter helps you automatically repair issues when you're blocked from installing or removing programs.

If you cannot open your Outlook data file or suspect that the file is damaged, use the Inbox Repair tool (scanpst.exe) to repair errors in the file.

If a Microsoft 365 application such as Word or Excel isn’t working correctly, sometimes restarting it will fix the problem. If that doesn’t work, you can try repairing it. When you’re done, you might need to restart your computer. The steps to access the repair tool vary depending on your operating system.

From the Overview page, select Office apps and on that page, find the Microsoft 365 product you want to install and select Install. To install Microsoft 365 in a different language, or to install the 64-bit version, use the dropdown to find more options.

Use the Office offline installer to install Office 2016 or Office 2013 if you don't have an active Internet connection or you're having problems with slow speed or unreliable connections.

The Microsoft Support and Recovery Assistant works by running tests to figure out what's wrong and offers the best solution for the identified problem. It can currently fix Office, Microsoft 365, or Outlook problems.

Learn how to remove malware from your PC. Use Microsoft Defender Antivirus in Windows 10 or Windows 11 to scan your PC for malware, viruses, or other threats.

If you already redeemed a product key, you're simply reinstalling the apps, or you know you have an assigned license through work or school, you can skip ahead and go to the section sign in to download and install Microsoft 365 or Office.

Contact Microsoft Support. Find solutions to common problems, or get help from a support agent.