forums.wsusoffline.net

With version 8.0 on windows 7, I NOT checked Windows Defender definitions, but at every run it was downloaded.

See attachment

(Sorry for bad english)

You have the checkbox set to include MSSE as that's the antivirus definition file.

MPAM = signatures for Microsoft Security Essentials (the full antivirus)
MPAS = signatures for Windows Defender

Your signatures are clearly the MSSE ones.

Sorry, i've not understood ..

Must I simply uncheck microsoft security essential to do not this file every time ?

Yes

AFAIR they will be downloaded once per day if the file verification is enabled in download generator.

but ... why dont' do this ?

- retr file info via ftp
- if size and date is not modified since last, then NOT redownload

They are not downloaded if source is identical. But MS use load balancers and also updates the files multiple times a day. These load balancers are not always properly synchronized or some cache-effect come into effect so the downloader may see a different version and downloads it again.

Some mirrors do not seem to send correct filesize info in the headers. Wget (the downloader used) always re-downloads on filesize mismatch.

but ... why dont' do this ?

- retr file info via ftp
- if size and date is not modified since last, then NOT redownload

Does that already, for all downloads. If you read the console window you can see it for yourself. If WSUSOU didn't use the timestamping option all downloads would be re-downloaded all the time.