I have lots of problems with cabal - not sure why or how to correct them. ghc-pkg check reports tons of issues, but all seem to be haddock-html, which doesn't sound too serious, or haddock-interfaces. Warning: haddock-html: C:\Users\guthrie\AppData\Roaming\cabal\doc\wxdirect-0.90.0.1\html doesn't exist or isn't a directory ... Cabal install errors, For example; C:\Users\guthrie>cabal install gloss-examples Resolving dependencies... Configuring gloss-raster-1.7.4.4... Building gloss-raster-1.7.4.4... Preprocessing library gloss-raster-1.7.4.4... [1 of 2] Compiling Graphics.Gloss.Raster.Array ( Graphics\Gloss\Raster\Array.hs, dist\build\Graphics\Gloss\Raster\Array.o ) Warning: Couldn't figure out LLVM version! Make sure you have installed LLVM ghc.exe: could not execute: opt What is LLVM, and do/how I need to install it? and another (of many) - perhaps unrelated: C:\Users\guthrie\AppData\Roaming\cabal\bin>cabal install wxc Resolving dependencies... <command line>: cannot satisfy -package Cabal-1.10.2.0: Cabal-1.10.2.0-db589dd5d526d3111ac2fde0f9ab986c is unusable due to missing or recursive dependencies: array-0.3.0.2-8e9cd0144e87fa9cc86cc9031631c4f3 base-4.3.1.0-f520cd232cc386 346843c4a12b63f44b containers-0.4.0.0-18deac99a132f04751d862b77aab136e directory -1.1.0.0-3a2367d72569467a8af8a231656ff1b8 filepath-1.2.0.0-f132e9f7703da4e20a47f f2b9acf1ea1 old-time-1.0.0.6-445ce39cbcebd38069c25c0f383b728d pretty-1.0.1.2-abc 7c632374e50e1c1927987c2651f0f process-1.0.1.5-b3dded8e54a2e13d22af410bdcfafff4 (use -v for more information) cabal: Error: some packages failed to install: wxc-0.90.0.3 failed during the configure step. The exception was: ExitFailure 1 Trying to resolve them: C:\Users\guthrie\AppData\Roaming\cabal\bin>cabal install base Resolving dependencies... cabal: internal error: impossible I've had several others, not sure if they are package specific issues, or some larger issue with cabal and libraries. So I tried to fix them from a suggestion in SO; delete the ~/ghc & ~/cabal files and restart cabal, by a "cabal install cabal-install". It gives: C:\Users\guthrie>cabal install cabal-install Resolving dependencies... In order, the following would be installed: deepseq-1.3.0.0 (reinstall) changes: array-0.4.0.0 -> 0.3.0.3 containers-0.4.2.1 (reinstall) changes: array-0.4.0.0 -> 0.3.0.3 old-time-1.0.0.7 (new version) directory-1.1.0.2 (reinstall) changes: filepath-1.3.0.0 -> 1.2.0.1, old-time-1.1.0.0 -> 1.0.0.7 ... cabal: The following packages are likely to be broken by the reinstalls: time-1.4 wxdirect-0.90.0.1 random-1.0.1.1 haskell-platform-2012.2.0.0 QuickCheck-2.4.2 ... ghc-7.4.1 ... Cabal-1.14.0 process-1.1.0.1 haskell98-1.1.0.1 haskell-src-1.0.1.4 haskell-platform-2011.2.0.1 haskell-src-1.0.1.4 haskell-platform-2011.3.0.0 ghc-7.0.4 Use --force-reinstalls if you want to install anyway. Lots of things there that I don't want to break, but not sure how to proceed. Even trying a -force-reinstall just gives more errors and failures... Running ghc 7.4.1, and Haskell platform 2012.2.0.0, cabal reports: cabal-install version 0.14.0, using version 1.14.0 of the Cabal library.