MacPro 2013 SSD upgrade/migration question

I have one of those trashcan MacPros from late 2013 that I’m upgrading. It has a 256GB internal SSD that has been the bane of my existence for the last 7 years or so and I’m finally putting in a 1TB drive in there. (Yes, I bought the correct one with my model number listed – I know you can’t just buy any ol’ internal SSD.) Maybe now I can finally re-install XCode (which I had to trash because I kept running out of hard drive space.)

Anyway, I digress. Putting it in is easy enough but I realized that I’m not sure what to do afterwards to make my life easy and seamless. I believe the only other time I’ve changed a boot drive, I just cloned it over to the destination drive, and then swapped out the drive. In this case, I believe I will be putting in the blank hard drive but … then what? It’s been so long since I’ve done any of this.

So what do I do? I have a blank hard drive. How do I install the OS to begin with? I do run Time Machine, so can I just restore off that on the new drive once the OS is installed? I would assume so. I also do have an external enclosure that takes your standard desktop and laptop hard drives, but I’m not sure if this new drive is compatible with the connections.

Given that, what’s my easiest course of action? I can figure this out with trial and error, but I might as well consult the great minds here.

Also, @beowulff because I know he deals with Macs.

If you have a good, solid Time Machine backup, you can restore from that onto the new, blank drive.
But, what I typically do is buy a cheap external USB 3 enclosure for the new SSD, and clone directly onto that using Carbon Copy Cloner, before removing the existing SSD. Then, you just pop the new SSD into the machine, and you are ready to go.

Yeah, that’s what I’ve done before, but I’m not entirely sure what enclosure is compatible. The interface is supposedly an Apple-designed PCIe 2.0 x4 i, so I can’t quite figure out which one works, as in which of those are important. Am I just looking for PCIe enclosures or something more specific (whatever those numbers at the end mean.)

That’s what I was worried about.
It looks like the MacPro will take NvME SSDs, if you are running a new enough operating system. I’ve put them in many MacBooks. If you had bought one of those, external enclosures are widely available.

I think you might need to create a Bootable OSX flash drive to boot the Mac Pro, and restore your data.

Looks like the Envoy Pro enclosure is the right one – it like $50 or so. Hmm… I’m not sure I feel like spending another fifty on this, so I’ll try restoring it from Time Machine and see how it goes.

Well, it seems to have worked. Probably would have been more seamless had I just spent the $50 on an enclosure and cloned the original, but I figured it out. Blank drive in - mash a bunch of buttons until I figured out the right one to get to a screen where I could format the hard drive (one recovery option did not recognize the hard drive; the other one did. I can’t remember if it was command-R or option-command-R. The one with the world logo on it did not work; the one with the apple logo did work.)

So an OS got installed, but I couldn’t Time Machine any more recently than November of last year, even though I had just done a backup last night. After making a second Time Machine copy to a blank drive it only dawned on me this morning when I saw the Mojave OS startup that perhaps it’s because I was running Big Sur on the original SSD. (I guess the little recovery loader just loads up the latest 10.x OS, and Big Sur is 11.1? That’s my guess.)

Anyhow, that did the trick, but I couldn’t restore from Time Machine, I had to use Migration Assistant, and a bunch of licenses and whatnot had to be restored and everything, and then there were a couple other issues, but after about three hours of tinkering I think I’m fully restored (hopefully I solved the random crashing issue that I didn’t mention.) If not, I could always plunk down the cash for that enclosure and clone the original drive, which would have been the most painless solution (as you mentioned) to begin with.

Glad you got it working.

My main machine is a Hackintosh, and I always dread doing a system update on it…