I'm trying to update Windows Defender (on Win 10) using definistions stored on a UNC path.
I'm setting the path the the mpam-fe.exe file like this
Set-MpPreference -SignatureDefinitionUpdateFileSharesSources \\path\to\mpam.exe
Then I'm running Get-MpPreference to verify that the path was set (it is). Once I verify that the path is correct for SignatureDefinitionUpdateFileSharesSources I run
Update-MpSignature -UpdateSource FileShares
I instantly get the error
Update-MpSignature : Virus and spyware definitions update was completed with errors. At line:1 char:1 + Update-MpSignature -UpdateSource FileShares + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + CategoryInfo : ObjectNotFound: (MSFT_MpSignature:ROOT\Microsoft\...SFT_MpSignature) [Update-MpSignature], CimException + FullyQualifiedErrorId : HRESULT 0x80070002,Update-MpSignature
This failure happens almost instantly. Just to verify that the specific powershell instance can access the fileshare in question - I followed it up by just executing the mpam-fe.exe file and it worked.