I did do a search. The posts I found weren't really clear or it wasn't similar to my situation. A friend of mine upgraded to the new iP4S and she's been using it for several days now with her own AppleID. However, since iTunes Match happened, I wanted both me and her to have access to it but keep it separate how she purchases Apps (she should use her own). So, I did all the settings correctly and logged her and logged in with my AppleID. Triple-checked it. But, that error message kept coming, "Device already associate with another AppleID, wait 90 days..." Never got this before, so I went into my iTunes account and "Manage My Devices" There is 4, all of my appropriate iProducts, but hers was not there. I didn't see how to add, there wasn't clear option. So, I logged in to her account in iTunes and went into the same section and of course, her device was associated with her AppleID. I figured if I removed from the account, her device will no longer have any association at all. Both accounts do not list her iPhone as a device that's authorized. Tried logging in/out with no success. Same error message. Is there anyway around this? I'm really confused why there is that error when both account do not have that phone listed. Shouldn't it list itself on the first AppleID it logs in to now? I doubt there is, but can you manually add a device? Or is this strictly a internal process? I don't really want her to wait nor does she that long. Especially since when I turned on iTunes match on her phone, it deleted all the music on her phone. Any help? Assistance? And oh yeah, the music in my iTunes, we've shared most of our CD collection together and now the digital, completely 50%. However, she doesn't own a computer, just her iPhone that she connects to my computer. I'm the one that stores all of it digitally, while she has it physically. Her music is my music vice/versa. Thanks in advance for any help.