Does this work for 1.5.1 builds?Back up your save. Delete the NEI folder and NEI.dat from the individual save's folder. There is an NEI folder and an NEI.dat just inside the saves folder delete those as well. If this is a server you are playing on you need to look in the folder that has the same name as the IP of the server.
I'm trying to get my multimc set up working, and some textures (vanilla and modded) don't show up. NEI version 1.5.2.10
Tried with and without optifine, deleting and readding NEI, clearing the player .dat, and your suggestion that's quoted.
It only effects half of my game saves, and the first time it happened, it was in the middle of game play.
(Note, this isn't in tech support because it's not currently in any of the launcher provided modpacks)