Quest items not registering

[Lord walter Mountbarren]

Does anyone know why on certain quests I make a kill or pick up logs or grapes but it does not register to the quest? Do i need to abandon and restart?

[DotComm]

Because you're in a raid group.

Because you're not killing the right things.

Because you've got addons installed that interfere with the quest log - disable all of them and try again, then enable them one by one until you find the problematic one.

[Stigg]

Although I don't think this is what you are looking for, but I don't understand completely...

Quests logs also track what is in your bank. So if you need to gather 20 grapes, and the quest says you have completed it but you cant complete it, then chances are some are in your bank. i.e. you have 12 on you and 8 in your bank.

Dont think that helps, but if not, then the above poster is heads-on!