Assuming this is a generic IC, in Parts editor try File->Save as new part (which will write your part to the mine parts bin) Then edit the part in the mine parts bin and replace the schematic and it will likely work. What is likely happening is that Fritzing thinks this is a generic IC (because the family in the fzp file is generic IC) and the parts factory is substituting a standard schematic in place of the one you specified so it can change the part labels (I just ran across a case of this a while ago.) Exporting the part divorces the new part from the parts factory and the substitution no longer takes place. The eventual solution will be to fix the parts factory but that is likely a ways away yet and this works now .
This likely indicates corruption in the user directories. If you don’t have a lot of local parts just clearing the directories will work (Fritzing will create new ones when it doesn’t find them). If you have local parts, then the best bet is to right click on them and specify Export part which will write them as a .fzpz file which can be reloaded in to the cleared user directories via File->Open->part.fzpz . I do this as a matter of course with all new parts so I have a backup outside of Fritzing. The directories are here (depending on operating system):
There are two user directories (with your parts and the parts database) which don’t get touched during an install (to not affect your sketches during upgrades). On Windows they are in
c:\users\username\AppData\Fritzing\roaming\Fritzing (which is a hidden directory so you need to enable hidden directories in explorer) and
c:\Users\username\My Documents\Fritzing (where username is your windows id)
If you don’t have any parts or sketches you want to keep you can just delete those two directories and Fritzing will recreate them, or you can move them aside by renaming them if you wan to keep something in them.