There have been some problems with interactions between this software and antivirus software.
For example, AVG did not like CC386 3.87. However, it currently thinks CC386 3.88 is ok. Other antivirus software has similarly flagged CC386 as being a problem on occasion; there have been reports that simply repackaging the software with a different EXE packer can sometimes alleviate the problem.
Another issue that has been reported is that with the current version of the compiler, attempting to generate code that links to MSVCRT.DLL or CRTDLL.DLL gets some antivirus programs to call the program that is being compiled a virus. Using the static library is ok though.
I'm not sure what to do about these issues for the long term; for now I am just watching them.