I'm using Code::Blocks 20.03 on Windows 10 (64-bit) and use MSYS2-64 with its gfortran compiler and GDB debugger.
I can compile and link a program with no problem and I can run through the entire program from Debug. When I try to step through the program, however, I get the output below. I have full rights to the source directory and all the code in it. It's not just this one program but any program I try to debug that causes the error.
Starting debugger: C:\msys64\usr\bin\gdb.exe -nx -fullname -quiet -args "D:/LANGS/FORTRAN/Calculating PI/bin/Debug/Calculating PI.exe"
done
Setting breakpoints
Debugger name and version: GNU gdb (GDB) 9.2
Child process PID: 16472
Cannot open file: /d/LANGS/FORTRAN/Calculating PI/montecarlo.f90
At /d/LANGS/FORTRAN/Calculating PI/montecarlo.f90:13