Hi, sometimes when I start ghci, I just get a segmentation fault. Sometimes I get even 15 segmentation faults in a row, and sometimes I can open it many times and it works each time. I downloaded the Haskell Platform for Mac, 64Bit, from http://www.haskell.org/platform/mac.html I verified the SHA1-Sum, btw. I tried reinstalling the platform, and I tried deleting the ~/.ghc directory, but nothing works. I didn't do anything fancy with Haskell, I just downloaded it yesterday and I didn't tamper with any haskell-files outside of my home-directory. The only kernel extensions I have installed are the ones from VMWare Fusion and maybe flux. (i'm not sure if flux involves kernel extensions or how deeply it messes with the OS.) michael@MacMichi:~ $ rm -rf .ghc michael@MacMichi:~ $ ghci GHCi, version 7.4.2: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Segmentation fault michael@MacMichi:~ $ uname -a Darwin MacMichi.local 10.8.0 Darwin Kernel Version 10.8.0: Tue Jun 7 16:32:41 PDT 2011; root:xnu-1504.15.3~1/RELEASE_X86_64 x86_64 michael@MacMichi:~ $ ghci GHCi, version 7.4.2: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Segmentation fault michael@MacMichi:~ $ ghci GHCi, version 7.4.2: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Prelude> sum (takeWhile (<10000) (filter odd (map (^2) [1..]))) 166650 Prelude> Any insights on what is really going on behind the scenes will be appreciated. Regards, Michael