Depth Analysis on System Restore Error 0x80070091 and Method to Stop Restoring the Windows 10 System is a very task and can be executed easily even by a novice users. However, sometimes you may notice alerts like System Restore Error 0x80070091 on the screen while executing the restoring process. This error generally occurs when there is a bad sector on an external hard-drive. This is the primary cause but there could be other reasons as well as such as malware attack. This is a very common error message and people are talking about this issue in various Online forums. This error is irritating and occurs every time when you restore an infected System. Microsoft is also aware that users are facing System Restore Error 0x80070091 on frequent basis and thus it too has provided a solution to fix the problem and they have been mentioned below.