To avoid undue efforts and waste no time, it’s much easier to completely reset Windows Update service and agent to the default state. The number of possible errors that an administrator may encounter when analyzing the Windows update log is dozens ( a complete list of Windows Update errors) and the process of resolving them is non-trivial. Usually, to debug Windows Update errors, an administrator needs to analyze the error codes in the log file %windir%\WindowsUpdate.log (in Windows 10, you can get WindowsUpdate.log in this way).
