Common occurrences when installing the .Net framework 3.5
Missing KB2966826; KB2966827; KB2966828
If the KB’s exist the article below is very helpful on the resolution
The article from http://www.askvg.com/fix-0x800f0906-and-0x800f081f-error-messages-while-installing-net-framework-3-5-in-windows-8/ details how you can fix the issue but I had a caveat in my encounter.
You look at the DISM error logs and you do see error as described in the article above.
DISM Package Manager: PID=1108 TID=1940 Failed finalizing changes. – CDISMPackageManager::Internal_Finalize(hr:0x800f081f)
But when you look in security updates you don’t see any of the KB’s that support .Net Framework 3.5
Usually the issue is referencing the sxs directory using a UNC path.
Copy the sxs directory to the local server, then run your DISM Powershell command as shown below.
dism /online /enable-feature /featurename:NetFX3 /all /Source:E:\sxs /LimitAccess