I have a problem with the TAB-Key that is usually used to swap weapons. The key works normal for some time, but then at the beginning of some mission it ceases to work. I can re-map the weapon swapping to another key, which then works. I can also re-map it back to the TAB-key (the mapping function DOES recognize the TAB-Key when I press it) but it does not work anymore for swapping weapons.

The only remedy is to validate my game data, which means finding a single damaged file and replacing it. Then the TAB-key works again.

But this happened already TWICE, so what damages my local data?