Trying to complete the older, top rated RPGs and currently working through IceDale II from the Ultimate Collection. Running into a problem in Chapter 5, Magical Grossroads for the Yuan-ti in Kuldahar. After I go through the magical entrance and during the first conflict, my game crashes to desktop and I receive the following message "An Assertion failed in CStore.cpp at line number 200." I tried deleting the cache without success. I am not using any mods. If the game is corrupted and I need to reinstall the game, which files do I need to save to continue my current game?

Go into the program files and there should be a folder called "mpsave". Your saved games are in there, and you should back up your most recent save before the error occurs, and a couple from maps before that, just for luck. Reason being, sometimes the game needs to reload the map you are in so that the fix will work, as the map that is saved also "saves" the error.

For the same reason, you need to have that area reloaded after you empty the cache. If you didn't it's worth a try, as that may save you a reinstall.

I can't recall a bug in that area, but it's been a while. Are you patched? There is a patch (2.01?) for IWDII.

This page in Polish describes a same problem as yours.
http://phx.pl/forums/index.php?showtopic=2611

Apparently it is caused by having container items in your inventory (bag of holdng, scroll case etc...)

Aerich, tried deleting the cache again and reinstalling the game with limited success. The number of crashes have slowed down, but they are still happening. ZFR, is the site specific toiwards what container item causes the crashes or is it a certain of container items. I just purchased the merchant bag of holding before the crashes started. I will sell that back and see if that helps. Thanks for the help.

Is your game patched?

I patched the game today. Still had the error and game crashes, but at a slower rate. I have not been able to sell the merchant bag of holding yet.

After selling the Mercenary Bag, I have been able to play a couple of hours without crashing.
Thanks to everybody for your help.