Mac Mini M4 upgrade NVMe disk after purchase, Can I

1) The SSD of the Mac mini is not upgradable after purchase. Order the storage that you might need in the foreseeable future. Of course, you can always add external storage along the way.

2) The M4 base mini can support 8K resolution at 60Hz via Thunderbolt or HDMI, but limited to two displays in that configuration.

Mac mini - Technical Specifications - Apple

1) Nope' none of the new Silicone Mac mini's are not upgradable.

If you have the 256GB model, you can move and store your large Media Libraries on an External Drive.

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

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

and > Move your iMovie for Mac library - Apple Support

and > Move a Final Cut Pro library - Apple Support

If you do move any of your Media Libraries, it is wise to use at least two external drives.

One drive for the Libraries and one drive to backup the Mac and Libraries.

2) In addition to the Mac mini spec's that D.I. Johnson posted,

also see > Connect a display to Mac mini - Apple Support

Apple provides no guidance on replacing the NVMe of any Mac mini, or in any M series Mac at all.

Apple doesn't condone modification of the M series computers and doing something like this is certain to void any warranty that your Mac may carry.

Unsanctioned modifications cannot be discussed in these Communities as that violates the terms of use.

Neither Apple nor any Apple Authorized Service Provider will upgrade the storage capacity of the M series Macs after purchase.

Yes, it can be done by someone super qualified, however any modification will immediately invalidate the warranty and very possibly ruin the machine. So if you don't mind ruining the machine and invalidating the warranty and feel you are qualified to make the modification go for it. It's your money and time so you can do with it what you please.

Macs made for the past 5-10 years have not been intended to be user upgradeable. If you need more storage than the base 256GB then it would be wise to buy the machine pre-configured with it or buy an external SSD.

As others have said it is madness to contemplate modifying the M4 mini.

What you can do is buy a 1 TB Crucial NVMe for £60 and a Thunderbolt enclosure for £70 - £100.

You then have 2 options.

You can use the Thunderbolt drive as a normal external drive or you can install Sequoia on it and use it as the boot drive.

I use the second alternative as it preserves your tiny internal drive and all the wear and tear takes place on the external.

Although I now have a Thunderbolt drive doing this, for the past year I was using a cheap £7 USB 3.0 enclosure to run my M2 mini and surprisingly it was just as fast as using the internal.

So why did I move onto the Thunderbolt? Just to see what I was missing in performance and the answer is, "Very little!"

Doing what I suggest is extremely simple, quite cheap (compared with Apple's £400 for 1 TB) and does not invalidate your warranty when you destroy your computer!