Created attachment 592626 [details] partition space search fails When Anaconda fails to install (see the screen) it should specify how much free space it needs and how much it failed to find.
I mean how much it found.
Created attachment 592627 [details] layout when a setup fails Here is a layout that may be the reason of the failure and why Fedora should contain more info.
Did I mention that my system is screwed up when pre-upgrade incorrectly calculated required space, failed during upgrade and was unable to rollback? It was. I had to install the system from scratch on different HDD after that.
The space reporting should be much better in F18. If you continue to experience problems there, please feel free to reopen this bug with comprehensive data so we can attempt to reproduce your exact problem. Thanks.