Mmh, that's a tough question as i have not experienced this so far.

I remember to have used a separate install of BH-RT for this mod only, as this is not a 'common' mod which you normally put in the Mods folder, but is instead directly put in the Data folder and some dll's need to be overwritten. Just pointing this out as a first check of how you installed this mod. When debugging, one simply needs to check step by step.

In my experience tho', other mods do not necessarily interfere with the CFCS mod, but vice versa, the latter has an effect on other mods in the same install. Nevertheless, i hope you installed everything according to the CFCS manual. I would advise having an install like f.e.: C:\BH-RT\Run\Data. Could be any other drive than C:, but putting it on the root of a drive, has brought me personally less trouble.

So i understand you were able to start a game and save it. Did the crash happen immediately on the first map? Was this part of a chapter/scenario? Is this happening with one particular map or all maps? A lot of information is needed and questions need to be answered in a debugging process.

Often, a crashing map can easily get fixed, but in case of a corrupt save file, i have to be pessimistic and fear there's no magic wand to fix it, as this could happen for a number of reasons. I have experienced this because of a specific unit, even the unit's skin, or when a unit started firing, but it could also be due to the lua script.

I do share the frustration that comes with it and for me, this is also the reason why i always use multiple saves for one map. However, if this only happens once, it doesn't necessarily make the game useless. The CFCS mod is a good one, in my opinion, and you could try to skip this map simply by using the cheat code. One bad map doesn't make the mod entirely bad. I know, it's not a real solution, but a bypass to continue a chapter f.e.

What i would suggest, is that you go to the CFCS topic on this forum directly and ask for help there:
https://blitzsrbija.proboards.com/thread/2373/crimson-fields-skies-cfcs-thread?page=10
Maybe the author SquireJames or other members could share their thoughts. Explain what map it concerns and where exactly, at what point, is this happening. You could try to share your .sav file...