I have "Error VSP1039 : VSInstr does not support instrumenting binaries built with prevous version of the compiler." When trying to use MSTEST on a set of tests. It is trying to instrument a 3rd party DLL, which is indeed compiled in VS6.0. I don't want it to instrument that DLL, only "my" code, but I do not see any way of ignoring the error, or getting it to not attempt to instrument it. I presume it is aggressively following all dependancies it detects my code uses (dll import / pinvoke on that DLL) /IGNOREWARN:1039 appears to not be allowed (presumably because it is an error not a warning) If I edit the test configuration, it only allows me a granularity of "per project" on and off, and it is a large project that happens to include at one point the use of that 3rd party dll.