Can I use an external 1TB SSD for all files and applications on a Mac mini M4 Pro?

Gary Willard wrote:

Well a few places, but a mention here as well...

Mini M4 with home directory on external d… - Apple Community

...such as this one - "people who have relocated their home user folders may find their setup broken again after a macOS update patch. This occurred multiple times with Monterey, and I saw some reports this occurred with Ventura as well. A relocated home folder is an unsupported configuration that will break again."

[...]

The problem the author of that post experienced was because they removed their Home folder from the startup drive to another disk. That is in fact an unsupported configuration and can easily cause problems. It is unrelated to using an external drive as the startup disk.

When using an external disk as the startup, the OS and the user Home folders will remain in their proper locations relative to each other on that external drive. If you don't move a Home folder from the startup drive on which it is first installed, then no problems are created. External startup drives are a common and supported configuration for Macs.

I have saved space in two different ways:

Made a bootable external drive using carbon Copy Cloner. Works great but then AI will not work if that is important to you or

Just move all large categories (Movies, Photos, Music) to external drive and leave all else on internal. You could also have your documents folder on the external if needed.

These two are the easiest and safest to maintain the Mac integrity without any major issues.

I always use an NVME drive in a TB enclosure to maintain speed if using to boot.

Gary Willard wrote:

... when the M4 is ready, then plug in the external SSD drive to use as a 'second' drive and 'point' (or use an alias) from the M4 to the iMac backup on the external SSD to get to the various Documents, Applications, etc that are on the external SSD?

First, regarding Applications, they need to be installed on the internal SSD in your mini. Just copying Apps from your iMac to an external drive, then plugging the external drive into your mini, will not make the Apps usable on your mini. (While there may be certain exceptions, most apps just won't run that way. They have to be installed.)

Second, regarding Documents, "etc." it depends on what you mean by "backup." If you mean you have copied folders & files from your iMac to the external drive, ok. But if you mean backup your iMac to the external drive using Time Machine, that is not advisable and it may not even work for what you want to do.

Third, you have to be cognizant of file & folder Permissions. In your scenario you should probably set that external drive to "Ignore ownership on this volume" so you don't have to deal with Permissions issues.

Gary Willard wrote:

is it possible to exclude those large file categories when using the Migration Assistant? Or put another way, would the Migration Assistant recognize that my 850GB backup is larger than the 512GB internal SSD and ask specifically what I want to move to the internal?

No, migrating your user data is all or nothing.

One option: move your Photos, Music, iMovie Libraries to an external drive before migrating to the new Mac mini.

Move your Photos library to save space on your Mac - Apple Support

Change where your music files are stored on Mac - Apple Support

Move your iMovie for Mac library - Apple Support

Second option: return the 512GB Mac mini and buy/order one with a 1T or 2T internal SSD.

Buy Mac mini - Apple

For ease of use and continuity, I personally recommend going with the 1T or 2T option.

Gary Willard wrote:

... is it possible to exclude those large file categories when using the Migration Assistant? Or put another way, would the Migration Assistant recognize that my 850GB backup is larger than the 512GB internal SSD and ask specifically what I want to move to the internal?

I didn't notice your mention of Migration Assistant before I wrote my earlier reply. I thought you just wanted to copy things from your iMac to an external SSD and then connect & use the SSD on your mini.

So, you want to migrate your apps & user data from your iMac to your new Mac mini, correct? Migration is an all-or-nothing thing. Or at least there is little control over what is migrated ... the limited choices are: Applications, Users, "Other Files & Folders" and System & Network. There is no further granular control; you'll get everything in each of those categories.

I suggest that a better approach is the following:

• Do fresh installs of your apps on your new Mac mini. You may actually *need* to do fresh installs if the versions on your iMac are too old to run on Sequoia on the new Mac mini.
• Transfer your data files (Documents, etc.) to your Mac mini by either:
  • Use a network connection. Connect your mini to your iMac via your network and copy your data files to your mini via the Finder
  • Use your external SSD drive. Use the Finder to copy your iMac data files to your external SSD, then connect the SSD to your mini and use it as your data drive.

I have no issues booting from an external clone. It updates fine with each OS release just as if I was using the internal.

Thanks for the info.

I have not relocated my home folders.

I simply installed the OS on the external and set it up afresh as if it were a new computer.

As mentioned already you should use the external as the boot drive and just ignore the internal.

Install macOS on it and run your mini from that. Very easy and quick to do.

I can give info if required.

Interesting use case, I think probably going to work unless your iMac is Intel based, some applications may not work if that's the case.

It is relatively easy to move documents to external drive, to make it super easy you can just create a shortcut of your document folder on external SSD and drop that shortcut to your original document folder. You can do the same with applications but not very elegant, and LaunchPad might not capture apps sitting on external drive.

Words of caution if you move home folder to external drive, or boot from external drive: USB-c connector is fragile and I would even say unreliable, slight movement to connector may severe active connection and you might end up in big trouble. It is less risky if you only have general documents/files sitting on external drive, but it is a completely different story when you have system-dependent files on external drive. Furthermore, I think AI don't work when boot from external drive, in case you need to use it.

I have never found USB-A or USB-C connecters to be fragile and as the mini is a desktop there should be minimal movement.

If AI is required and does not work it only takes seconds to boot back into the internal drive.

I have a bootable 1TB SATA SSD in a USB 3.0 enclosure (Total £60) and a bootable 1TB NVMe in a Thunderbolt enclosure (Total £130).

I booted from the first one for a year and was able to assess its performance compared to the internal SSD.

Subjectively everything felt the same but on timed tests of video rendering and exporting the very slow (360MB/s) SSD took around 4% longer than the internal which is fairly negligible.

A few months ago my curiosity got the better of me and I forked out the readies for the Thunderbolt NVMe (2,800MB/s).

Yep! It was faster in so far as it rendered and exported around 4% quicker but that is such a small increase that in every day use it is not noticeable.

So was it worth the extra cash? Probably not.

However, there is just one time when the faster drive shows its paces and that is when copying massive files . . . something which I rarely do, so just for you I have done a test copying a 31GB folder.

The Thunderbolt NVMe did it in 26 seconds whereas the USB 3.0 SSD took a massive 2 minutes 42 seconds.

If you are a professional where time is money and you are copying hundreds of GBs a day the time saving may be worth it but if you are like me and unlikely to copy anything for another year it definitely isn't.

The point is that if you get a dead cheap USB 3.0 enclosure (under £15) if you find it is not fast enough you can then fork out another £70 upwards for a Thunderbolt one and you have only lost a tiny amount.

Of course you may be a member of the Musk family with cash burning a hole in your pocket, in which case ignore everything I have written!

SORRY! This was directed to the OP.

Be easier to migrate to and use the external full-time, if you want to follow that path.

Trying to run while split across two SSDs is going to be an ongoing project.

Where have you read that upgrades etc. are an issue? Balderdash!