Download and install or reinstall Microsoft 365 or Office 2021 on a PC or Mac

Microsoft 365  or Office won't install: Your computer must be running a supported operating system to install Microsoft 365 or Office. You can find a list of which systems are supported on the system requirements page. For example, your install won't be successful if you're trying to install Microsoft 365 or Office on a computer running Windows Vista or Windows XP operating system. If your computer can't install the full desktop version of Microsoft 365 or Office, try the free Microsoft 365 apps from your browser.

I received an error message: If you got an error message while trying to install Microsoft 365 or Office and it has a Learn More link, select it to get information for how to troubleshoot that particular error. If there wasn't a link, see Troubleshoot installing Microsoft 365 or Office.

I received an unsupported operating system message: If you got an unsupported operating system error message you may be trying to install Microsoft 365 or Office on an unsupported device such as installing the Mac version of Microsoft 365 Office on a PC or vice versa, or trying to install Microsoft 365 or Office on a Chromebook or other mobile device. See Unsupported operating system error when installing Office or Set up Office apps and email on a mobile device.