The official explanation from SEGA reads as follows:

“After the game was finished, Nvidia released a new set of drivers which we were unable to test before release. Unfortunately this has caused some incompatibilities with the game. We recommend that you roll back to the previous drivers until this is resolved”

In addition, it seems that Empire Total War also bugs its fans with several Steam installation issues, which can be resolved by quitting and restarting it whenever necessary. A fix for these issues should arrive soon.

Last but not least, there’s a bit of bad news for those still using FAT32 drives. Due to the large size of the game, FAT32 will not work with the title unless the user doesn’t converting the hard drive to NTFS.