Windows update error 800b0001 indicates that either the Windows or Microsoft update program was unable to determine a service provider or that a required catalog store file is corrupted. This error code can appear as either WindowsUpdate_800B0001 or 0x800B0001 and can be fixed by using the System Update Readiness Tool.
The System Update Readiness Tool, known as CheckSUR, scans the computer for any issues that may be causing the update error to occur. Should CheckSUR find any problems or bugs, it will attempt to repair the issue. CheckSUR may also encounter problems while running, all of which will be recorded in a file called CheckSUR.log located under the Windows folder inside the computer's hard drive.
If the program is unable to repair the issue, a Windows repair may be necessary. This repair is not the same as a reinstallation of Windows and will not affect any files or programs currently in the computer. After the Windows Repair is complete, a proper Windows Update cycle should be rerun to install any files that are missing or are necessary updates to the operating system.
Should the Windows update error continue to occur, it is usually best to contact Microsoft directly for expert troubleshooting.