Windows Update failing with error 0x80004005? Learn what causes this update error, why it blocks installation, and the step-by-step fix.
The update download cache is corrupted.
Next step: Open Command Prompt as administrator. Run: net stop wuauserv — delete the folder C:\Windows\SoftwareDistribution\Download — run: net start wuauserv — then retry.
The Office Click-to-Run service has a conflict.
Next step: Close all Office apps completely, wait 30 seconds, and try the update again via File → Office Account → Update Options → Update Now. If that fails, use the Office Repair tool.
The installer doesn't have write access to a protected folder.
Next step: Right-click the installer → 'Run as administrator'. If it's an auto-updater, check the application's settings for a 'run as admin' option.