Whenever an NPC gives me an item it does not show up in my inventory, also when I'm am supposed to steal something from a container it doesn't show up. I can't really complete any of the Thieves Guild side quests because of this. I am on the quest Diplomatic Immunity for the Main Quest and when Delphine gives me the Party Clothes and Boots they do not show up in my inventory. Somebody please find me an answer this is pissing me off to no end!

I'm not sure about stealing. haven't done that yet. When NPCs give you a quest item—as opposed to a gift or item you can actually use—this may be deliberate. that way they don't clutter your inventory.

No, dude this has happened with everyone that gives me an item, at the top left of the screen it shows the items the person gave me but when I go into my inventory the item is not there.

I have this exact same issue.

Questitems don't show up in the inventory.
Both items in my own inventory and items in chests, other bodies etc.
I know they are there because I've used the "showinventory" command and it shows then, but not in the menus.
Happens to me frequently.

A couple of examples (minor spoilers):
1. Couldn't get the skeleton key from dead body.
2. Couldn't get Sabjorns shield from a chest.
and probably 10 more.

I've been solving it with "setstage", but I don't want to do that.
Here's a link below with a savefile. Can't take the crown from the body:
http://www.mediafire.com/?j0jxn8uy9hacjpl

For some reason i can't get your save to load.

Come on people! Reply!

Weird. I've uploaded another save here:
http://www.mediafire.com/?6199k8sdzzxlb1c
Can't get the amulet fragment from body.