Adding
cmd.exe /c "ECHO error : unexplainable"
causes this:
1>------ Build started: Project: xxx, Configuration: Debug Win32 ------
1>EXEC : error : unexplainable
1>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V110\Microsoft.CppCommon.targets(134,5): error MSB3073: The command "cmd.exe /c "ECHO error : unexplainable"
1>C:\Program Files (x86)\MSBuild\Microsoft.Cpp\v4.0\V110\Microsoft.CppCommon.targets(134,5): error MSB3073: :VCEnd" exited with code -1.
========== Build: 0 succeeded, 1 failed, 1 up-to-date, 0 skipped ==========
It happens only when 'error' string is followed by a ':' character.