Mac Mini with 2 Internal HDD, how to see what's only on each drive separately

The new APFS format is a change-up from previous drive formats. Without getting into too deep, what you are seeing is an anomaly. You really should only be seeing a single drive. The fact that you see two suggests that something is wrong there.

I see that you've bought a new Mac mini with only 256 GB of internal storage. I believe that is going to be problematic going forward. We see too many users banging their heads over storage issues that arise especially with 256 GB drives. Few veteran users here will suggest buying any new Mac with less than 500 GB of storage and many will suggest 1 TB as a minimum starting capacity in today's computer world, myself included.

Applications and OSs continue to increase in size and the last thing you want to worry about is how much storage you don't have when things get tight. "Gosh, I think I bought too much storage" said no one, ever.

Neither the RAM nor the internal storage of the modern Mac cannot be increased after purchased due to the way Macs are now built. There is no way to increase the RAM, and the only way to increase storage later is to add external drives.

I suggest you quickly return this Mac mini and buy one that is more future proof, with greater internal storage. If you bought directly from Apple, then you have a 14-day window to return it, no questions asked. If you bought from a retailer, your return wind may vary.

And a good rule of thumb is never buy a new computer that has less internal storage than the one you are replacing.

Follow up -

Hennesseystealth wrote:

[...]

Is there a way to look at each drive and only see what's on that drive? Something like Windows File Explorer where you see C: and D: etc. and just the content of those individual drives (or partitions).

Thanks in advance for any help.

Yes, the Finder application is the interface between you and your folders and files on the Mac drive. Open a new Finder window to navigate your drives, files and folders.

Use the Finder on Mac - Apple Support

But, as I posted previously, seeing two drives on your desktop with identical content is an anomaly.

Double check the year model of your Mac mini.

Identify your Mac mini model - Apple Support

The last Mac mini's with dual HDD bays were the 2010, 2011 and 2012 year models.

If it is a 2014 year model, then it could have a Fusion Drive consisting of 1 HDD and one smaller Flash Drive.

Regardless I concur with D.I. Johnson that you should return that Mac mini with the 256GB storage drive.

Then order the one with 500GB or better yet, the one with 1T of storage and just migrate everything to it.

Or.. optionally you can try Migrating just your User settings from the old Mac mini to the new Mac mini and then manually copy everything else over to the 1T drive in the dock.

Yeah' the 2010, 2011 and 2012 models could be configured as dual drive server versions.

To check the year model if it is running, go to Apple > About this Mac.

see > Identify your Mac mini model - Apple Support

From there click on the Storage tab and lets have a look at how much space that you are using on the drives.

For example: I using my 2012 Mac mini Media Server with a single 480GB SSD.

Instead of taking a picture, use Command Shift 4 and take a screenshot to post.

see > Take a screenshot on Mac - Apple Support

Returning to your original question:

Hennesseystealth wrote:

[...]

The current Mini shows two drives on the desktop (HD1 and HD2), but when you open them they show the same data. Is there a way to look at each drive and only see what's on that drive? Something like Windows File Explorer where you see C: and D: etc. and just the content of those individual drives (or partitions).

Thanks in advance for any help.

If you want to visualize the contents of HD1, just double click the drive to open a Finder window. Then do the same for HD2 and you have two open Finder windows. Resize and position those windows next to each other to directly compare the contents of those drives and their folders and files.

Hennesseystealth wrote:

I’m on my iPhone so screenshot isn’t an option. Turns out I actually have 2 1Tb drives. One appears to be used for Timemachine and is almost full. No real reason it should be keeping that many backups.

No but that would be handy to have for migration to a new Mac mini with a large enough drive.

I’ll check settings on that one. The second drive has 400Gb used. Only about 4Gb in apps.

The new Mac mini has all of the latest macOS app's already installed.

Problem is that 400GB is not going to Migrate into the new Mac mini's 256GB storage drive.

One work-around if you can not return that Mac mini and get one with 1T of storage space.

Is to format the 1T SSD in the Dock using Disk Utility and install macOS on it.

see > Use an external SSD as your startup disk … - Apple Community

Then Migrate to it from one of the Mac mini's internal drives.

see > Transfer to a new Mac with Migration Assistant - Apple Support

No Migration Assistant can not split up your data into two different locations.

Time Machine can not be pruned without damaging the structure.

When you migrate from Time Machine, it only migrates one copy of all of the accumulated data.

iCloud is not a Mac backup that you can migrate from or fully recover from.

It is only intended to be used for sharing files between your macOS and iOS devices.

Disregard any comments about your new mini's small drive.

Yes, it is too small but the solution is to spend £100 on a 2TB NVMe in a USB-C enclosure rather than £200 to add another 256GB internally.

The basic mini is a bargain but once you start adding any internal storage or RAM you are getting yet another grossly overpriced Mac with little or no improvement to performance.

I have the old M2 and the new M4 both with 256GB internal drives but with external NVMes as above. Even the lowly M2 with 8GB RAM easily copes with anything I throw at it when editing 4K video in FCP/Resolve.

So embrace your new mini and get an external NVMe.