Both the 32-bit Microsoft debugger and the 64-bit Microsoft debugger are installed.

When using a 32-bit build of QtCreator, the x64 toolchain for Microsoft Visual C++ is properly detected, however, the Debugger is set to "C:\Program Files (x86)\Debugging Tools for Windows (x86)\cdb.exe".

If using a 64-bit build of QtCreator, the opposite case is true; i.e., the x86 tool chain for Microsoft is properly
detected but the debugger path is set to "C:\Program Files\Debugging Tools for Windows (x64)\cdb.exe".

In both cases, the line-edit/browse button/auto-detect buttons are greyed out and you cannot change them and you cannot change the path. The only work around is to Clone the architecture that you need and manually set the path there.

The proper path should be detected and/or you should be able to manually edit the path.