Dear code::blocks team,
Today  I downloaded code::blocks with mingw compiler, but after installation when I opened code::blocks I got a message saying that compiler was not found. I resolved this issue with the following steps: 
1. Click on Settings
2. Click on Compiler
3. Click on Toolchain Executables 
4. Enter the following data:
   a)for compiler's installation directory enter: C:\Program Files (x86)\CodeBlocks\MinGW\bin
   b) for C compiler enter: x86_64-w64-mingw32-gcc.exe
   c) for C++ compiler enter: x86_64-w64-mingw32-g++.exe
   d) for linker for dynamic libs enter: x86_64-w64-mingw32-g++.exe
   e) Debugger remains the same
   f) For resource compiler enter: windres.exe
   g) For make programs enter: mingw32-make.exe
5. Click OK and code::blocks should work without any problem.
This is a workaround until compiler autodetection is not fixed. 
Regards,
Stojan