The ld warning is benign. You can safely ignore it. It is a known issue with GHC and the latest Mac OS X tool chain, and we are stuck with it for awhile:  http://hackage.haskell.org/trac/ghc/ticket/5019 The best way to remove versions of Haskell on a Mac is now my shiny new Mac uninstaller! I just put out a "release candidate" yesterday. You can find it here: Source: UninstallHS.hs  (just runhaskell this)Executable: uninstall-hs.tgz  (unpack and run if your ghc is broken) Running without will just list what's there and suggest what to do next. It is "dry-run" by default.  - Mark PS.: "rm -rf ~/.ghc" only removes the package databases, not the packages themselves. It also removes your ghci configuration, so I don't recommend it.