High Sierra upgrade onto new SSD

Hi TomTheMacFan! (Nice nickname btw) I just recently had to do the same thing with my 2012 MacBook Pro. For me I was very worried about this process as well. Fortunately enough though, it was surprisingly simple. If you want to keep your data, then make sure you back it up to an external USB hard drive or a cloud backup (and copy the files over when you are done with the steps. If you don't want your data, just skip to step one.

1.) Go ahead and switch out the drives, you can watch how to do this here (for your 2010 Mac model of course) : https://www.youtube.com/watch?v=jd3RS-GGsCI

2.) Go ahead and boot up your Mac as normal (it will act weird booting up)

3.) By default, every Mac has a base (Recovery) OS. This base OS has drive formatting tools and macOS install capabilities. Go ahead and have your Mac download and install macOS on that SSD. NOTE: What every OS your Mac came with is going to be the OS it installs on it! So don't be surprised when you see an older version of macOS (for me it was El Capitan)

4.) Allow the OS to install, and I would recommend setting it up as a new Mac, then importing your files at a later date.

5.) Since you are going to have an older OS, go to the App Store and download and update to High Sierra.

6.) At this point, your Mac should be working properly on macOS High Sierra.

If you have any problems during this process, please feel free to reply to this thread and I'll help you out to the best of my ability.

Best of luck!

techguy5000

I would clone your internal Sierra drive to the external SSD (formatted HFS (Journaled) then update the external drive to HS. Your internal drive formatted to HFS will not work with the external drive if formatted to APFS. I would then test out the external drive and HS to see if any issues. If all OK then do the swap. I always do that to be sure the new OS works like I expect. If not I still have my original internal drive and OS that does work. I always use CCC for cloning but other ways work as well. No issue on SSD wear. Later if you reinstall HS on the internal drive (now SSD) it will reformat the drive to APFS.

I wouldn’t worry about wear and tear on the drive. However, you might want to format your new SSD using Sierra’s Disk Utility, since there have been reports that Disk Utility has been made even less capable in High Sierra: for example, not even “seeing” unformatted drives. Nor would I undertake this without having a drive enclosure on hand in which to install the new drive, format it, clone, and then boot from the clone. Perhaps this is what you mean by “USB adapter”?

Frankly, I would not install High Sierra at all at this point. There is no compelling reason to do so this early in the (insanely accelerated) release cycle. If your current system is working fine, wait.

You may find this helpful:

Is It Possible Not to Convert to APFS When Upgrading to High Sierra? | Other World Computing Blog

High Sierra will only auto format to APFS if it is an internal drive. When you do the upgrade on an external SSD it will not make it APFS. I did what you are doing so I know from experience. If you later swap out the internal drive for the HS external drive it will remain with HFS (journaled) format. However, if you should boot into recovery mode and pick "reinstall OS" I'm sure at that time it would format to APFS. That I have not tried but makes sense.

Have not tried it, but

I've had a long time back used a Unix Disc - to partition => and then I did the mac install side by side that.

https://www.techrepublic.com/article/how-to-revert-back-to-apples-hfs-from-apfs/

I've been running Samsung SSD without trim for last 3 years and no issues but only have filled about 60% of drive which keeps it more efficient.