Hi Thomas I suspect the problem you are having is specifically with Pandoc. Pandoc has a couple of dependencies on C libraries: network and zlib are two - they are part of the Haskell platform so they would be working in the first place (I have a mostly vanilla install of Haskell platform on Windows and whilst Haddock does appear to be broken via ghc-kpg check, the other libraries / tools are fine*). Pandoc also depends on the zip-archive library which then depends on the digest library. Digest seems to depend on C internals of the zlib library. Now, zlib package is part Haskell platform and it includes a binary library of (the C) zlib and the source headers, so it might be possible to build digest by itself but you might end up needing cygwin or MinGW / msys (I've built it just now under Cygwin). Trying to installing digest before Pandoc is one possibility - if it fails, at least it will show if further attempts to install Pandoc are going to be futile. [*] The broken packages you listed from ghc-pkg check appear to be caused by cabal chasing the extra dependencies for Pandoc but then failing part way through the whole installation. Some of them look like plain Haskell packages to me (utf-8string), rather than bindings to C libraries, so if they were installed individually I'd expect them to work. Best wishes Stephen