The identity of the backup disk “AirPort Extreme” has changed since the previous backup. The disk may have been replaced or erased, or someone may be trying to trick your computer into backing up to the wrong disk. Use this disk Don't Back Up The backup disk image “/Volumes/Backups-1/5k.sparsebundle” could not be created (error (null)). This is what I keep getting. I have a brand new Airport Extreme and a 5 tb seagate external harddrive hooked up to it via the usb 3.0 cable. Followed the full instructions on apples website, formatted it to OS X Extended and all that jazz. I can access the hard drive though the network just fine. I can put whatever folder or files I want on there manually, access them, delete them, all works as it should. However whenever I try to do a time machine backup, it never finishes. The text on top is what it's giving me right now, it did the first 30 gigs or so then stops. I don't have a screenshot but I remember it said something about this drive has changed, I could click to continue using it or opt not to so of course I opt to continue. Then it brought me to this screen. On a whim, I directly plugged the drive into the back of my imac though the usb3 cable and it backed up properly overnight. No problem at all, yay. But when I ejected and put that external drive into the Airport Extreme, time machine doesn't recognize that backup and keeps trying to create a whole new file. It won't recognize that it's the backup it just made a few minutes ago. Any ideas how to fix this? This is all brand new equipment and I specifically bought the 250 dollar Apple router instead of a cheap linksys to avoid this nonsense, I made sure the computer isn't going to sleep so that's not the culprit. Thanks so much in advance!