Mysterious verifier.dll

Question

While debugging the crash on customer's machine we noticed that our application runs under verifier.dll. e.g each thread stack starts with verifier.dll and every system function is intercepted with verifier.dll stub.

Common sense and running Google search for "verifier.dll" clearly indicates that this dll belongs to Application Verifier tool provided by Microsoft. However the stunning fact is that Application Verifier not even installed on customer's machine (appverif.exe not found on client's machine neither c:\Program Files\Application Verifier directory),.

What else could cause the program to run in such mode.

Answer 1

Sounds like a virus scanner type thingy. However I suggest you use process explorer to look at the dll and where it's loaded from and and other such info.

Answer 2

Application Verifier is a debugging feature of the operating system, so it is always there. It can be configured by modifying the registry even if you haven't got the Application Verifier tool installed on the system.

This article on MSDN gives details of the registry settings that control the debugging features of the operating system. It might be that someone or something has enabled application verifier on the system that you are seeing the exception on. If it isn't specifically enabled for your process it might have been enabled system wide.