Why Don't My DLL Breakpoints Work?
This topic lists reasons why breakpoints might not work as expected in DLLs and solutions or workarounds for each case.
You cannot set a breakpoint in a source file when the debugger has not loaded the debug information for the module where the code is located.
Symptoms may include messages, such as the breakpoint cannot be set. The Warning breakpoint glyph appears at the breakpoint location. These Warning breakpoints become actual breakpoints when the code is loaded. For more information, see Breakpoints.
This may occur in cases such as:
Attempting to set a breakpoint in a DLL before LoadLibrary is called.
Setting a breakpoint in an ActiveX server before the container has started the server.