Ranger 7.2.1 installed on Server 2012 with local SQL instance.

Reports worked before and suddenly stopped working generating error (see screenshots attached.

"The report definition is not valid. Details: Deserialization failed: The element 'TableColumns' in namespace ...... has incomplete content"

Newly created reports do not work either.

It is not a Ranger issue. Visual Basic Command line compiler crashes in WSUS.

https://social.technet.microsoft.com/Forums/windowsserver/en-US/269e1a1c-2e81-45f9-a0ce-e271d99361f0/visual-basic-command-line-compiler-crashes-in-wsus?forum=winserverwsus

Two recent .NET updates are the culprit. 

https://support.microsoft.com/en-us/kb/3118750

The fix was to uninstall updates 3098779 and 3097997, and then install .NET 4.6.  Reporting now works!