Comment 28 for bug 218230

I also think it might be a more general problem, but as it seems, on my computer it was caused by trackerd. I tried to disable the use of tracker by removing it from my session and disabling it completely. But apparently it is started automagically as soon as the file dialog is opened, which is strange enough.

It then produces heavy network/disk activity (home is on a nfs share), but this doesn't seem to be the main reason the file dialog blocks, because after some time the dialog opens fully functional but the disk activity remains. If I manually kill the trackerd during the blocking period, the file dialog comes up immediately.

For now I moved /usr/bin/trackerd to somewhere else and put a symlink to /bin/true there instead, which solves the issue for me. Of course this diables trackerd completely, but I haven't really used it.