Two Macs accidentally cloned/linked during migration

[wanderluster]

I just upgraded my old (2010) and new (2014) Macbook Airs to Yosemite, then did a data migration. All looked well, so I disconnected the ethernet cord used for the migration and began deleting data from my old Macbook. Then I realized the same data had mysteriously vanished from my new Macbook. Now everything I do on one Mac, its consequences show up on the other - like if I view websites on one computer, the history shows up on both Macs.

Have my two Macs fallen crazy in love and are conspiring against me so I'll never separate them? Did I somehow clone them? Or does this maybe have something to do with my Macs now being connected to the Cloud?

Would you please tell me how to unlink my Romeo and Juliet Macs?

Thanks. While you smart people are helping me out, I'm going to try to figure out how to restore my Chrome bookmarks despite this new OS apparently not having users, libraries, or anything else I'm used to...

 

[redheeler]

If the two are attached to the same iCloud account and your Safari history is syncing over, you can disable this in System Preferences > iCloud and uncheck Safari.

 

[wanderluster]

Hey Red - thanks for the response. That didn't turn out to be it (I use Chrome, not Safari, and iCloud doesn't synch Chrome), but your suggestion helped me stumble on the answer.

I did a few more experiments with Firefox and other apps and realized the computers were only synching Chrome, nothing else. So I went into Chrome preferences and found it was set to 'synch all' between devices where I was logged in to the same Google account. It may have been synching since I upgraded to Yosemite or even before, but I didn't notice until I started deleting bookmarks.

Managed to restore the bookmarks I erased by replacing my bookmark file with bookmarks.bak. It's crazy that with Yosemite you have to hit option + Go in Finder to even see your library.

Thanks again for the help!