Most importantly: backup your SHIV folder often, so that you can always go back when something went wrong. I have four or five backups at various stages, starting right after installation, and ending with my final modded setup.
I initially had sometimes CTDs, but they have now been mostly banished.
CTDs related to SH4 data
During patrols you should not change anything in the SH4 data (graphic and sound files are ok), otherwise you may not be able to load your saves again.
Example: I edited renown for a single ship and got a (reproducible) CTD on loading all of my savegames. Put back the old file and everything went back to normal.
SHIV seems more touchy in that respect than SHIII. My theory is that it keeps more data in its savegames, which leads to crashes when the old data that which is referenced has changed.
CTDs related to sound
Since I created my own sound mod I had a lot of sound related CTDs.
I had only very few CTDs since I made the following changes (so few that it doesn't bother me any more):
- installed the latest driver for my soundcard
- reduced (DirectX) hardware sound acceleration to 'Standard'
- use only sound files that are reasonably short (15s instead of 10mins as in some mods
)
- use no sound files that are stereo (this was recommended in some forums, however in the original UBI files stereo/mono as well aws bitrates are mixed up too)
- removed a certain radio mod that allegedly has dangling references and causes CTD at a defined point in time
- use a reasonably large pagefile for Windows (lest the system runs out of memory)
Which was the main problem I cannot say. It could be all contribute to the problem, it could be none, but all of these measures potentially improve stability.