Try these steps in order:
- If File History uses a USB or other external drive, make sure the drive is physically connected to the PC.
- Open Control Panel > System and Security > File History.
- If the drive is no longer selected correctly, choose Select drive and reselect the external drive.
- If File History is set to a network location instead, in Control Panel > System and Security > File History, reselect the network location.
- After reconnecting or reselecting the drive, wait for the next scheduled backup.
- To test immediately, in Control Panel > System and Security > File History, select Run now.
If File History still does not recognize the drive, File History can be configured again from Control Panel > System and Security > Save backup copies of your files with File History. If no drive is selected by default, use Select drive, choose the external drive, and select OK.
File History backs up libraries such as Documents, Pictures, Videos, and Desktop. Other folders can be added by right-clicking the folder and selecting Show more options > Include in library.