I don't know if anyone else has come across this issue but I'm stuck with this as this is possibly one of the most random glitches I have come across in Lion. I'll explain my situation in basic form... I bought an Iomega network cloud storage 1TB drive for time machine, I reserved an ip address on my WiFi router for it and setup the device with the setting I wanted, after a restart of the device and my macbook pro I started up time machine to do a full backup of my mac, this took around 2-3 hours so I left it to carry on doing it. then every 15 mins time machine would backup anything that had been changed this worked fine for exactly 3 hours. Then I get an error pop up "Time machine cannot use this device as it has the incorrect AFP settings" well thats total rubbish as you just backed up yourself for the last 6 hours or so absolutely fine no issues, so I restart the mac and the network hard drive this then ruined my finder setting in fact they became corrupted so I had to delete the .plist and restart this fixed the issue, so I checked the setting on the network hdd and decided to delete the mac setting form the hard drive and start again to see if the NHD would now work, it did and again was backing fine for 2-3 hours until boom done the same thing again same error message and the same .plist corruption? I'm sure that this issue is with time machine or the Iomega software as sometime that fails to load up, I've updated them both including the drive firmware to the latest version as this is supposed to fix the glitch with apples updated AFP but it still fails after a set time, I think this issue is with the fact there is no keychain access for authenticating the NHD so I think time machine forgets the user name and password for the drive and so the Iomega drive won't let time machine log into it thus causing AFP errors, but I re-authenticate manually and it doesn't even try just immediately throws up AFP error, time machine is kind of rubbish to be honest I've seen better.