Please, update the game with the last patch, or make it available for the GOG version.
I cannot restart mission and cannot install the 1.3 patch because it is not compatible with GOG version (asks for CD).
Don't bother. I've been seeing the same issue for years now. Tried various system setups, to no avail. Made lots of reinstalls with my retail version of IGI 2, applied all patches available but none of all this will help. Until patch 1.2 the game was widely unplayable on recent systems. However that 1.2 patch also seems to introduce that restart freeze bug. Unfortunately this issue has not been resolved with patch 1.3. I guess we're not going to see a fully working version of IGI 2 anytime soon. The game may be deeply flawed but it was still fun sometimes :(
Reloading saved games (not available on difficulty level 'David Jones') seems to work, but that will also keep you from reaching the highest rank 'David Jones' in each level...
According to GOG.com, their download is only patched to 1.2
The loading screen of my (unaltered) GOG version shows '1.3'. Still 1.3 will not bring any improvement on that issue.
I bought it on GOG in the promise of a better tomorrow, a working copy of IGI 2 ;'(