0x80070643

Use Windows Defender Command-Line Tool to Update the Signatures
Alternately, you can use the Windows Defender command-line tool
MpCmdrun.exe to update the signatures. Open an Admin Command Prompt
window and type these two commands exactly:

"%ProgramFiles%\Windows Defender\MPCMDRUN.exe" -RemoveDefinitions -All
"%ProgramFiles%\Windows Defender\MPCMDRUN.exe" -SignatureUpdate

The first command removes any installed signature and engine files,
and this option is used when you have difficulties trying to update
signatures. The 2nd command checks for the latest updates and installs
it. In case the 2nd command fails with an error, use the alternate
command to update the definitions directly from the Microsoft Malware
Protection Center (MMPC) servers:

"%ProgramFiles%\Windows Defender\MPCMDRUN.exe" -SignatureUpdate -MMPC