If you receive Windows Update error 800F081F, it means that Windows Update or Microsoft Update cannot determine the cryptographic service provider, or a file Windows Update requires (named catalog store) is corrupted. The System Update Readiness Tool can correct some conditions that cause this error. To use the tool, follow these steps:
Go to the System Update Readiness Tool
webpage. In the Information for advanced users section, find the Windows edition and system type of your computer, and then click the link to download the System Update Readiness Tool. To find your edition of Windows, see View your computer information.
Run Windows Update again.
Typically, the scan takes 15 minutes or less, but it can take longer on some computers. The Windows Update progress bar isn't updated during the scan, and progress seems to stop at 60% complete. This behavior is expected. The scan is still running and you shouldn't cancel the update.
The System Update Readiness Tool (CheckSUR for short) is a program that performs a one-time scan for problems on your computer that could prevent you from installing updates. The problem above is one of the conditions that the CheckSUR tool can check for and repair.
If the CheckSUR tool encounters problems while running, it records them in a file called CheckSUR.log, located in your Windows folder, under Logs\CBS\.
On a default installation of Windows, this will be C:\Windows\Logs\CBS.
If the System Update Readiness Tool does not correct the problem, you'll need to repair Windows. Repairing Windows won't damage your personal files or the programs that are installed on your computer.
Once you finish the repair, you'll need to rerun Windows Update to install any updates aren't included on the installation DVD. To repair Windows, follow these steps:
Close all programs, and then restart your computer.
Insert the Windows DVD into the computer's disk drive. Wait for Setup to start. If Setup doesn't start automatically, follow these steps:
Click Start, and then type Drive:\setup.exe in the search box, where Drive is the letter of your computer's DVD drive (for example, D:\setup.exe).
In the Programs list, click Setup.exe.
Click Install Now.
Click Go online to obtain the latest updates for installation (recommended).
If you are asked for it, type the Windows Product key.
In the Which kind of installation do you want? window, click Upgrade.
When the installation is complete, restart your computer, and then run Windows Update.
If you continue to see this error, try this automatic troubleshooter, or go to the Microsoft Answers
website for more assistance.
Error codes this applies to: