Microsoft Test Manager error in displaying test steps caused by malware

Sometimes the tool is blamed for errors which are not the fault of the tool – this is one such story.  It was however, not so easy to get to the bottom of it, so I hope sharing this story can help some others.

One of our test developers started to get this message inside the test steps part of a test case in the MTM.

saying “Could not load file or assembly ‘0 bytes from System, Version=4.0.0.0,……..”

The same error came up inside Visual Studio when we opened a test case there.

Then we noted a similar error on another piece of software – this error:

A System.BadImageFormatException, and same message as above, but just for framework 2.0.

We found this  description which pointed to a malware problem (See bottom of that post), that is a fake anti-spyware program called “Additional Guard”.  We checked the computer in question using Malwarebytes Anti-Malware tool.  It found and cleaned out 753 registry keys!!  After this cleanup operation the error was gone.  This is a great tool ! 

The “Additional Guard” program had been inadvertently installed, and then uninstalled afterwards, but the corrupted keys were of course not removed. 

We also noted that this computer had full corporate virus scanning and malware protection, but still this nasty little thing still slipped through.