I'm getting irreproducible validate failures on Windows. Here's the output: Unexpected failures: ghci/prog003/prog003.run prog003 [bad exit code] (ghci) plugins/plugins07.run plugins07 [bad exit code] (normal) plugins/T10420.run T10420 [bad exit code] (normal) plugins/T10294a.run T10294a [bad exit code] (normal) plugins/T11244.run T11244 [bad stderr] (normal) Framework failures: plugins/plugins07.run plugins07 [normal] (pre_cmd failed: 2) plugins/T10420.run T10420 [normal] (pre_cmd failed: 2) plugins/T10294a.run T10294a [normal] (pre_cmd failed: 2) plugins/T11244.run T11244 [normal] (pre_cmd failed: 2) th/TH_spliceE5.run TH_spliceE5 [ext-interp] ([Errno 17] File exists: '/c/Users/simonpj/AppData/Local/Temp/ghctest-zsi7djxa/test spaces/./th/TH_spliceE5.run') th/TH_reifyMkName.run TH_reifyMkName [ext-interp] ([Errno 17] File exists: '/c/Users/simonpj/AppData/Local/Temp/ghctest-zsi7djxa/test spaces/./th/TH_reifyMkName.run') th/T3395.run T3395 [ext-interp] ([Errno 17] File exists: '/c/Users/simonpj/AppData/Local/Temp/ghctest-zsi7djxa/test spaces/./th/T3395.run') th/T5508.run T5508 [ext-interp] ([Errno 17] File exists: '/c/Users/simonpj/AppData/Local/Temp/ghctest-zsi7djxa/test spaces/./th/T5508.run') th/T10828.run T10828 [ext-interp] ([Errno 17] File exists: '/c/Users/simonpj/AppData/Local/Temp/ghctest-zsi7djxa/test spaces/./th/T10828.run') I have no idea what the framework failures mean. But those plugin tests work ok when run one at a time .../tests/plugins$ make TEST=T10420 PYTHON="python3" "python3" ../../driver/runtests.py -e ghc_compiler_always_flags="'-dcore-lint -dcmm-lint -no-user-package-db -rtsopts -fno-warn-missed-specialisations -fshow-warning-groups -dno-debug-output'" -e config.compiler_debugged=False -e ghc_with_native_codegen=1 -e config.have_vanilla=True -e config.have_dynamic=False -e config.have_profiling=False -e ghc_with_threaded_rts=1 -e ghc_with_dynamic_rts=0 -e config.have_interp=True -e config.unregisterised=False -e config.ghc_dynamic_by_default=False -e config.ghc_dynamic=False -e ghc_with_smp=1 -e ghc_with_llvm=0 -e windows=True -e darwin=False -e config.in_tree_compiler=True -e config.cleanup=True -e config.local=True --rootdir=. --configfile=../../config/ghc -e 'config.confdir="../../config"' -e 'config.platform="x86_64-unknown-mingw32"' -e 'config.os="mingw32"' -e 'config.arch="x86_64"' -e 'config.wordsize="64"' -e 'config.timeout=int() or config.timeout' -e 'config.exeext=".exe"' -e 'config.top="/c/code/HEAD/testsuite"' --config 'compiler="/c/code/HEAD/inplace/bin/ghc-stage2.exe"' --config 'ghc_pkg="/c/code/HEAD/inplace/bin/ghc-pkg.exe"' --config 'haddock="/c/code/HEAD/inplace/bin/haddock.exe"' --config 'hp2ps="/c/code/HEAD/inplace/bin/hp2ps.exe"' --config 'hpc="/c/code/HEAD/inplace/bin/hpc.exe"' --config 'gs="gs"' --config 'timeout_prog="../../timeout/install-inplace/bin/timeout.exe"' -e "config.stage=2" \ --only=T10420 \ \ \ \ \ \ Timeout is 300 Found 1 .T files... Beginning test run at Thu Dec 8 12:02:23 2016 GMTST ====> Scanning ./all.T =====> T10420(normal) 1 of 1 [0, 0, 0] cd "./T10420.run" && $MAKE -s --no-print-directory -C rule-defining-plugin package.T10420 TOP=/c/code/HEAD/testsuite cd "./T10420.run" && $MAKE -s --no-print-directory T10420 SUMMARY for test run started at Thu Dec 8 12:02:23 2016 GMTST 0:00:13 spent to go through 1 total tests, which gave rise to 1 test cases, of which 0 were skipped 0 had missing libraries 1 expected passes 0 expected failures 0 caused framework failures 0 unexpected passes 0 unexpected failures 0 unexpected stat failures