Debug Error! Popup window about winafl HOT 4 CLOSED

Note that the pop-up is generated by the debug build of your target, not WinAFL. In the debug build, Visual Studio inserts additional checks and if erroneous condition is discovered, a popup such as the one you observed is created. These types of errors are different from program crashes and are not currently caught by WinAFL. In your example WinAFL does notice an exception with the code 0x406d1388 being raised, but I'm not sure treating this exception code as a crash is a good idea because the same exception code might be used during the normal functioning of the program (see for example: https://msdn.microsoft.com/en-us/library/xcb2z8hs.aspx). If you want to, you can create your own WinAFL build and add this exception code to the onexception() function inside winafl.c. Until then WinAFL is going to report this type of error as a hang. Note that this should only cause slowdowns if such errors happen very often in the target app.

BTW WinAFL treats the following exception coded as crashes
EXCEPTION_ACCESS_VIOLATION
EXCEPTION_ILLEGAL_INSTRUCTION
EXCEPTION_PRIV_INSTRUCTION
EXCEPTION_STACK_OVERFLOW

from winafl.

Are you running against a debug or a release build of your target?

from winafl.

I'm running a debug build. I never tried running on a release build.

from winafl.

Thank you ifratric. Switching to Release build solved my issue.

from winafl.