Dot Net 3.5 on Windows 10

10th October 2019

Sage application requires dot net 3.5 but new workstations are Windows 10. WSUS may be blocking the install of DotNet 3.5 Found a few articles on how to make this work here Error codes 0x800F0906 and 0x800F081F. Also a problem on Windows 8 but nobody uses that.

Microsoft recommends decompressing some files from the install media and using the following command Dism /online /enable-feature /featurename:NetFx3 /All /Source:<drive>:\sources\sxs /LimitAccess

I have used the fix above but decompressing files requires a chunk of disk space and it is not quick.

Another option is to turn off WSUS temporarily; Start, Run regedit.exe find the following key

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU\ UseWUServer=0

Restart Windows

After installing DotNet 3.5 remember to set the same registry entry to 1 to re-enable WSUS or you may get some untested updates installed. (occasionally M$ releases some flakey ones) A co-worker has tested this successfully.

Another article says you don’t need to disable all of WSUS, you can use this registry entry to tell Windows to get add-on components from WindowsUpdate and not WSUS. Need more testing to confirm.