I took delivery of a new 5k iMac two weeks ago. I set it up as new, signed into iCloud and was all set. My mail inbox loaded, iMessage logged in and picked up all history, FaceTime etc. All as expected. Yes I needed some two step verification but only once. Today I took delivery of a new rMB. I restored it from a Time Capsule backup of my MacBook Air on 10.10.3. It asked me to log back into iCloud etc - which I did. But, it then asked me to set up app specific passwords for a bunch of native Apple apps (FT, iMessage etc.) Plus it screwed up my Keychain access on my iPhone and Ipad. WTF!? I was asked to do the two step verification, which I did, but that does nothing to address the problem. Insists on app specific passwords. Again, two weeks ago I didn't need it. This seems completely random? Anyone got any ideas?