I am working on a merchant and I want to give him an inventory that replenishes. By studying some of the other merchants from the game I determined that adding a negative (-) sign in front of the amount of items I want him to sell will create the desired effect. However, when I try to do this in the CS it crashes! Am I missing something? Any help is appreciated.

Well, that's a doozy of a pickle. Just playing around in the CS with a new merchant I gave him a cuirass and a bow then set the values to -5 so he would always have 5 of each item on him for sale, and nothing happened. Also auto-calc stats, making him a blocked character or adding a script had no effect, which i thought might have been the problem. This question may have an obvious answer, but how are you altering the number of items in his inventory?

For instance:

-1 x weapon
-1 x armor
-10 x arrows

I place the items in a custom chest (common chest 2 with 500 capacity and 1.50 scale) that is owned by him, and then alter the number to read -1 or in the case of arrows -10. Also I thought maybe the content is making the CS crash. He is selling Solstheimian weapons and armor (not the ice variety) in Vvardenfell. Is there any known problems with this?

Ok, I've just had a bit of a play with a new merchant, and a chest that is owned by him which contains the same things that you have outlined, and placed both merchant and chest in caldera, with no ill effects - saving correctly etc. Have you tried just shoving them in the actual merchant's inventory? I doubt that would have any effect, but i cant see anything wrong with the way you have done it. This one has me stumped sorry

I'm guessing these are stock items from the Bloodmoon expansion. I'd suggest making sure you have Bloodmoon checked in your file dialog. Make the chest & place it but leave it empty. Save the mod & exit the CS. Then reload the construction set and your mod add the gear and save again. If it still crashes try rebooting your computer and adding a tribunal depency. The only thing that's making sense here is that there's some kind of data corruption involved such as left over data that's not part of your mod but the CS is trying to process as if it where part of your mod.