Claus, Simon, You'll recall the cabal-install problem you noticed recently where it decides it wants to re-install some core library like array or containers or whatever. I'd appreciate it if you could test the darcs version of cabal-install and see if it is behaving better now. It was choosing to re-install packages when the way it had chosen to configure the available version of the package (ie what exact dependencies it'd picked) did not exactly match those of the installed package. I've changed things so that it now picks the installed version when the additional constraints it adds (direct and indirect dependencies) do not conflict with the existing constraints. This means it'll pick the installed instance in many more cases and when it does not that there is a more legitimate reason. It still may have been possible to use the installed version if we had known that information much earlier and made different choices at an earlier stage. I've not yet added support for user supplied install constraints but I plan to shortly (eg --constraint='array installed'). Duncan