This is an odd problem that I have never had before.
I am working on a design and I closed the board, deleted a part in the schematic and then reopened the board when I realized the mistake I made. Now the PCB shows the part and the schematic does not. I cannot delete the part from the board.
I have tried adding the part back in the schematic, saving and then trying to delete. No go.
Typically you can recover from these things quite quickly. If you haven’t already, try this:
Close the schematic, delete the part from the board, save the board and re-open your schematic.
Otherwise, what message do you get when you try to delete the part from the board?
If you get a ‘Board and schematic are not consistant’ message when you open the board/schematic, you can find out why using the Electrical Rule Check (type ERC in the command line).
look at the backup copies - they will follow the form file.s#n & file.b#n where n is a digit, s for sch files and b for brd files. Say your board’s name is foo so you would expect to have foo.sch and foo.brd. You probably have foo.s#1 as well but no foo.b#1. I would copy foo.brd to foo-save.brd and foo.s#1 to foo-save.sch. Then open up foo-save.sch. Of course, you may have multiple foo.s#n files… pick the newest one.
eagle really should not allow deleting parts if there is an unloaded brd file (or at the least put up a warning). maybe they fixed that in V5.