0x80070020: a locked file stops Windows Update replacing system files
0x80070020 is a sharing violation during install, usually antivirus or backup software holding files. Clean boot, then rerun the update to clear it.
MSI 1306: The File Is in Use and Setup Cannot Replace It
Error 1306 and 0x80070020 mean real-time scanning or a running process is holding the file. Add correct install exclusions or move to a suite that behaves.
Outlook 0x80070020: The OST File Is In Use and Locked by Another Process
Outlook 0x80070020 means another process holds a lock on your OST file. Close ghost processes and exclude Outlook data files from antivirus scans.