After `pacman -Syu`, the ghc is upgraded to 6.12.1 %ghc --version The Glorious Glasgow Haskell Compilation System, version 6.12.1 However, the xmonad still stay as it is: %pacman -Q|grep -i xmonad xmonad 0.9-2.1 xmonad-contrib 0.9-1.2 %pacman -Ql xmonad|more ...... xmonad /usr/lib/ghc-6.10.4/ xmonad /usr/lib/ghc-6.10.4/site-local/ xmonad /usr/lib/ghc-6.10.4/site-local/xmonad-0.9/ xmonad /usr/lib/ghc-6.10.4/site-local/xmonad-0.9/HSxmonad-0.9.o xmonad /usr/lib/ghc-6.10.4/site-local/xmonad-0.9/XMonad.hi xmonad /usr/lib/ghc-6.10.4/site-local/xmonad-0.9/XMonad/ ..... So it will fail when running `xmonad --recompile` as xmonad cannot find its library in /usr/lib/ghc-6.12.1. Do i need to re-install xmonad ? Sincerely! ----- fac n = foldr (*) 1 [1..n] -- View this message in context: http://old.nabble.com/xmonad-cannot-find-its-library-after-upgrading-GHC-tp2... Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.