Argh! Again! The Windows build is failing. Here's the error: libraries\base\System\Posix\Types.hs:179:23: Not in scope: type constructor or class `CMode' make[1]: *** [libraries/base/dist-install/build/System/Posix/Types.o] Error 1 make[1]: *** Waiting for unfinished jobs.... Indeed base/includes/HsBaseConfig.h says /* Define to Haskell type for mode_t */ /* #undef HTYPE_MODE_T */ which means CMode doesn't get defined. The config.log file looks suspicious, note the line in red. I'm stuck Simon configure:13967: checking Haskell type for mode_t configure:13974: c:/code/HEAD/inplace/mingw/bin/gcc.exe -o conftest.exe -Wall -fno-stack-protector -Wl,--hash-size=31 -Wl,--reduce-memory-overheads conftest.c >&5 configure:13974: $? = 0 configure:13974: ./conftest.exe configure:13974: $? = 0 configure:14230: c:/code/HEAD/inplace/mingw/bin/gcc.exe -o conftest.exe -Wall -fno-stack-protector -Wl,--hash-size=31 -Wl,--reduce-memory-overheads conftest.c >&5 c:/code/HEAD/inplace/mingw/bin/ld.exe: cannot open output file conftest.exe: Permission denied collect2: ld returned 1 exit status configure:14230: $? = 1 configure: program exited with status 1 configure: failed program was: