Microsoft has released a patch error 0x80071a91 when you install Windows 8.1 Update
Immediately after the launch of Windows 8.1 Update on the official Microsoft forum (and not only there) began to appear numerous error messages faced by users while installing this update. The company recognized a one of these an error (0x80071a91) and released an official fix for it.
Many users still have not been able to install Windows 8.1 Update, but there are those who have this process finished successfully, but problems arose after the installation. For example, some users after the upgrade, the computer began to run significantly slower, while in others it erased the saved games. However, one issue that is at the end of installation fails with error code 0x80071a91, Microsoft has corrected by issuing a special patch (KB2939087). It is available through «Windows update» and on the official website of the company. After installing the patch you will have to restart the system for the changes to take effect.
Except for Windows 8.1 and Windows RT 8.1, this error can be faced by users Windows Server 2012 R2.
Let us know if this update helped you solve the problem, and if not, tell us about your problem in comments and we will try to solve it together.