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.

The Program Install and Uninstall troubleshooter helps you automatically repair issues when you're blocked from installing or removing programs. It also fixes corrupted registry keys. First, you'll need to download the troubleshooter.

Describes how to troubleshoot problems that occur when you install, uninstall, or upgrade a program on a Windows-based computer by using Windows Installer.

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. Run the System File Checker tool (SFC.exe)

If you have a volume license for Project 2016 or Visio 2016 and you’re trying to install the Click-to-Run version of Microsoft 365 Apps for enterprise, you can use the Office Deployment Tool to download and install the Click-to-Run perpetual (stand-alone) versions of Project 2016 or Visio 2016.

How to stay safe with a genuine Office license. Note: If you already bought genuine Office, but haven't installed it yet, make sure you Uninstall the counterfeit version of Office first. If you already installed genuine Office, uninstall both versions and then reinstall the genuine version.

If you're trying to install Office and you see an error message that says Administrative Privileges Required, or you see error code 0-1005 or 0-2005, it means you don't have the correct administrator privileges on your device or if you do have those privileges, you haven't provided the necessary permissions.

A Windows product key is a 25-character code used to activate Windows. It looks like this: Locate your product key for Windows 10 or Windows 11. Depending on how you got your copy of Windows 10 or Windows 11, you'll need either a 25-character product key or a digital license to activate it.

This security update resolves a Microsoft Excel remote code execution vulnerability and Microsoft Office information disclosure vulnerability. To learn more about the vulnerabilities, see the following security advisories: Microsoft Common Vulnerabilities and Exposures CVE-2021-31174.

Method 1: Windows Update. This update is available through Windows Update. It will be downloaded and installed automatically. Method 2: Microsoft Update Catalog. To get the stand-alone package for this update, go to the Microsoft Update Catalog website. Method 3: Windows Server Update Services.