First, for testing purposes, I think you don't have to start a game and enter battle
This should happen using the Training module : could you try it ?
If crash happens, this will make you save time for next steps
You mentionned you installed the commendations mod, and I know there have been some/many issues due to this one, but I cannot help you on this subject (I just don't use it myself)
Examples of crash that may be caused by a mod :
- a new sound is badly defined, i.e. the file related to this new sound does not exist or is not found : this should cause a crash as soon as you use the weapon, not before
- a weapon sprite is badly defined, i.e. related file is not found : this should cause a crash when accessing inventory
- ...
But in your case, you don't meet any issue running mods individually, so...
Perhaps installation is bad (files at wrong place could cause a crash)
Could you try this
1) Remove OpenXcom directory
2) Check if you don't have any OpenXcom folder under "MyDocuments", otherwise remove it too
3) Reinstall it manually :
- UFO Enemy Unknown Or UFO Defense (Original, see recommendations about this) : let's say under D:\OPENXCOM\Data
-> see attached screen shots for mandatory folders to be copied from vanilla game
- then OpenXcom under D:\OPENXCOM
-> exe and dll will be copied under D:\OPENXCOM
-> D:\OPENXCOM\User will be created => check it before running the game, and if not exists, just create it yourself
-> D:\OPENXCOM\Data subfolders will be overwritten/completed
- then your mods except commendations (so do not replace any exe or dll)
-> D:\OPENXCOM\Data subfolders will be overwritten/completed
PS : I am not really qualified to help you as I am a member as you, but often is it just a bad installation, so I try to help you and if possible, sometimes, save time for development team
In fact, I will redo same installation as you and tell you if I have a crash too