Software cannot be transferred it must be installed. If you have the CD it has the installation files for both OS on it ... if you used a download you will need to call TT support and get the MAC installation file pushed to your account. However you really don't need to install all 3 years unless you need to amend something.
To call TurboTax customer support
https://ttlc.intuit.com/questions/1899263-what-is-the-turbotax-phone-number
They are available from 5 a.m. to 5 p.m. Pacific time Monday - Friday
Assuming you used the Desktop software every year:
Your PDF and .taxyyyy datafiles need to be copied to the hard drive of the new computer
1) You can copy over all the PDF file you have for each of those years. You really need those files generated and saved from the original computers. The default turbotax directory is "C:\Users\name\Documents\TurboTax" where name is the name you've assigned to your new computer
2) you should also copy over the all the .taxyyyy datfiles...BUT...but only the 2015-to-2017 software can be re-installed on your new computer, so some of the earlier datafiles may be useless (some folks have indicated they can still install and update 2014 software...but there's no way for you or us to know if the State downloads for 2014, or earlier years are actually available or not, until you try....no promises.)
3) get your 2015-thru-2017 TTX desktop software re-installed on that new computer ASAP. You need either the CD/DVD, or the installation download file to re-install those years. Start a dummyfile on each and get in far enough to get your NJ state software installed. You cannot open any prior year datafile until the state(s) you used that are installed first. When done, go ahead and try to re-install 2014 or earlier...but if you find can't update the main software, or can't download the state software, then those prior years will be useless to you and you will have to rely on any PDF files you created on the other computers.
4) Once #3 is done, then you can <File <<Open Tax Return to browse to, and open any prior year datafile you saved and transferred to your new computer. After opening that file, and saving it once, it will then show up on the opening page of the software every time you start it up.
5) always save a PDF file copy every year after your e-file has ben accepted, but, while you may have done so when you filed, repeat it again AFTER your e-file has been accepted, and you re-checked its filing status from within the software itself (not thru any online status checks) . Checking your filing status from within the desktop software is the only way your acceptance gets logged into your actual tax file (an Electronic Postmark page). Save two PDF files, once as the file-only copy, and again as the extended PDF...... For Your Records copy with all forms and backup worksheets....
Other thoughts followup:
a) when you copy over the PDF files and datafiles, make sure you do use "Copy" and do not "Move" ....since a Move deletes the copy on your backup drive...you don't want to do that....something might get messed up or overwritten and you may need those files.....always maintain backup files off computer.
b) when you start a Dummyfile in step #3, if you save it , make sure you save it with a "Save-As" the first time saved, so you can give it a unique name like "Dummy2015"....you don't want to overwrite any of the transferred datafiles by accident.
