I know that's really a belated answer, but "later" is much better then "never". Anyway, I've started to play just a week ago. As I got to the root of this problem - the crush reason is Synda/Johnny when she/he is following you (only as companion) and when you are near this mod's special places (like the near Vos) as there is a certain glitch in their scripts (I've not tried to change that script yet). But there are can be another things that can crush it also (as I've a huge amount of mods installed at the same time), some of them were fixed and changed in TES Construction Set by me to prevent more crushes, but still... Mod mostly crashes near Vos (there are a lots of things to do and that is a really big problem for this Mod), sometimes in Sadrith Mora (again if companion(s) are with you). I've tried to leave companion far away behind (as stay here option) and then enter to the crushing place and it was all OK, but with them behind it certain crash. Sometimes it's good to get the old save and replay some quests, as is can get you to pass the problem place, but it takes a lot of time to replay their quests...
As for the software/hardware sound it's has nothing to do with this problem, as it was written for those who already have/had a weak PCs, so it could improve the game performance. The same goes for Windows 10, 8, 7, as it doesn't matter with version you've.
P.S. Edit, also this is important: NEVER use quicksave or quickload! These corrupt your savegame (this mod is using it's own quicksave, so sometimes it can bring problems if you are/were using your ingame quicksave). Always use a real save and rotate betwean several of them so you can go back to an earlier instance if you need to and not just the last save you made.
P.P.S. there is a second and updated version of this mod, so there are a lots of fixes (the first version is and was a real glitch).
And Final Edit (as I can see, a lot of things were fixed):
http://www.gamesas.c...ect-t48959.html (Underground 2 project fix topic)
http://www.mediafire...55zo2gusi3ffb9t (it's almost a final patch for the second version of underground)
Post the final edit: I'm playing a lot in that version and it working fine except some minor bugs (but those are not so bad att all).
BTW, there is one bug (not so bad, but it's spoil some normal playing) almost at the end of the Good Side Main Quest -> Underground Tunnel Passageway A Door isn't working from the Assurdirapal shrine which is inside of it (probably there is a bug in the script). It's possible to get there through the C Passageway which exits to the island with the Big Head's shack in Sheogorad Region -> the north/east most island or you can use console for that (to teleport) (case not sensitive): Player->PositionCell, 4367.782, 5456.266, 13063.396, 0, "Underground Tunnel Passageway A".
Edited by TOPMO3ABP100, 13 February 2019 - 08:33 PM.