I found it at last! Well kind of.
In the scenario files, after all main sections (policy, manpower, controlled provinces, etc.), there is a section called dormant leaders and bellow it the dormant units, I deleted both of those, basically everything after the provinces section, for Serbia, Slovenia, RSK and Srpska and now finally the game doesn't crash on first june. Now I just have to figure out which scenario file exactly it is and which part. The good news is that is not the SFRY file which has huge amounts of text, and it's not the events folder, since I didn't delete the events now.
It's most likely the "15000" units from the savedebug I mentioned in the previous post, I just don't know who those units belong to, 10500 belongs to some Serbian unit I think, actually I just checked the current savedebug, I left the 10500, but it doesn't show the "15000" units at all, so they must be in one of the scenario files I edited (Serbia, Slovenia, RSK, Srpska)
In the scenario files, after all main sections (policy, manpower, controlled provinces, etc.), there is a section called dormant leaders and bellow it the dormant units, I deleted both of those, basically everything after the provinces section, for Serbia, Slovenia, RSK and Srpska and now finally the game doesn't crash on first june. Now I just have to figure out which scenario file exactly it is and which part. The good news is that is not the SFRY file which has huge amounts of text, and it's not the events folder, since I didn't delete the events now.
It's most likely the "15000" units from the savedebug I mentioned in the previous post, I just don't know who those units belong to, 10500 belongs to some Serbian unit I think, actually I just checked the current savedebug, I left the 10500, but it doesn't show the "15000" units at all, so they must be in one of the scenario files I edited (Serbia, Slovenia, RSK, Srpska)