Today I decided to change the resolution of IWD2 from 1650x1080 to 1440x900 because I found that it hurt my eyes too much when the resolution is too high. Then when I loaded up my save file, all my equipment is messed up. In all the armor slots for all my charcters have magical weapons in them, so instead of wearing leather armor +1, I am now wearing a masterwork greatsword. And this is the same for all my characters (my druid is wearing a crossbow as armor?). It gets even weirder, my fighter is weilding a halberd and a tower sheild at the same time. Worst of all, all my previous items are lost and replaced with random magical items. Is there any ways to get my old items back, I dont have the heart to restart all over again.

It was a known error in the original cd-game as well. Different resolutions fuck up the game. Ideally you should play in 800x600 as the other ones aren't really properly supported, and the area you see doesn't get much bigger in the larger resolutions anyways.