I've gotten GHC to build on Windows, but the test suite is finicky. Here is an error I am getting: =====> T5267(normal) 50 of 3724 [0, 0, 0] cd ./arrows/should_compile && 'c:/Users/ezyang/Dev/ghc-validate/bindisttest/install dir/bin/ghc.exe' -fforce-recomp -dcore-lint -dcmm-lint -dno-debug-output -no-user-package-db -rtsopts -fno-ghci-histor y -c T5267.hs >T5267.comp.stderr 2>&1 Compile failed (status 256) errors were: T5267.hs:11:15: tee: standard output: Permission denied It consistently fails on this test, and when I look at the process list I see: I 1032 1548 1548 4064 con 500 14:54:08 /usr/bin/tee I was seeing something similar when I used parallel make, apparently there is a known deadlock when running make -j2 (or higher). But I don't know why tee would be deadlocking. Edward