2014-09-11, 10:43 PM
If you open project.dat it in a hex editor, it seems to always have a 4 byte long value of some sort. A long time ago when I was testing Tom's Diadem of Maunstraut, he didn't include project.dat in an update-patch and the game wouldn't start for me until he did. It's probably a checksum for the game's system file or such- a tamper protection.
The only way I can see it being a problem for your friend is if he updated from 1.1 to 1.2 without re-downloading the whole game, thus ending up with the v1.1 project.dat and the v1.2 game files.
The only way I can see it being a problem for your friend is if he updated from 1.1 to 1.2 without re-downloading the whole game, thus ending up with the v1.1 project.dat and the v1.2 game files.