It turns out that, last year, I did transfer my PHOTOS and MUSIC files to my DATA and MEDIA files, respectively, and they, along with my DOCUMENTS file, are also in iCloud. Thus, the file that is hogging all my storage on the Mac HD disk is my USER LIBRARY file, at 458 GBs, on the 512 GB (actually, about 490 GB useable) Mac HD disk. There isn't much else on the Mac HD, but the Applications file (5.2 GB), and the 2 Library files.
I have been reading all my files for my 2012 Mac Pro, including the Technical Repair pages, to find an answer to this conundrum . If I change out the disk (the easy part!), then I have to find a way to transfer all the current Macintosh HD information - including the User files - to the new disk - the HARD part! The Repair pages say that, in order to do that, I must use the Installation Disks (not Migration Assistant?), which I no longer have !?! From my reading of what seems like the entire Internet, it seems that moving the User files would be a VERY BIG MISTAKE that could lock me out of my Mac Pro!
Also, I have searched for replacement disks, and OWC has a 1 TB SSD for less than $100. HOWEVER...I have a 2009 Mac Pro, from which I have canabalized the Power Supply last year, for this same 2012 Mac Pro. The 2009 Mac Pro has two 640 GB and 1 TB drives in it. Could I use one in my 2012 MP?
AND...all this presupposes that I can find a way to move all the info from my current Mac HD to a new disk! I may never see again!
