I have a iMac (27-inch, Mid 2011) 2.7 GHz Intel Core i5-12 GB 1333 MHz DDR3 I have installed a Samsung SSD 850 Pro 128GB drive . I put a new install of Yosemite 10.10.2 on the SSD and have it booting to my new drive. I would like to know how to remove the OS from the old 1TB drive and move over my user information? I would also want to remove the OS from the old drive? Is this a possibility or have a going about it the wrong way. *****I may have not stated this correctly in the first post of my question.***** I have left the original 1TB mac drive installed in the system and added the second drive with the new installed OS.. So right now I can start up in what ever one I want to.
The easiest way would have been to create a time machine backup before replacing the drive, then use Migration Assistant to import your account, apps, etc.
However since you replaced the drive already, you will need to get an USB to sata connector, or external enclosure, to connect the old drive in order to access the data.
At this point you have 2 options
1 - Run migration assistant and point it to the external drive. It should see your old account and allow you to import everything. (Sometimes this fails, see http://www.hardturm.ch/luz/2014/02/fixing-os-x-10-9-mavericks-migration-from-external-volume/)
2 - Manually copy the data, or the entire account folder. The original account will be under the /Users folder on the old drive. You can copy the full account if you wish, then use system preferences to create a new account with the same shortname; it will prompt if wish to use this existing folder for the new user account. However, if you decide to try to copy manually you may run into permissions issues. You most likely will have to reset permissions on the folders/files but you can use BatCHMOD to do this (free). Be warned that I would not mess with permissions on the original drive in case of a problem, only work on the copies you make.