How to fix file transfer issues with USB C Drive enclosures on MacBook Pro

What is the exact make & model of both the enclosure & the drive? It's probably a problem with one or both. And did you install any drive utility that came with the drive?

Many Kingston SSDs are low end models which are not very reliable and have poor performance regardless of the computer being used. It is very hard to differentiate the better SSDs from the low end models regardless of manufacturer. Even professional product reviews are mostly irrelevant these days because the SSD manufacturers are now utilizing multiple different internal components which can greatly affect how the product performs & behaves with no distinction in model numbers.

I've never used a UGreen enclosure so I have no idea how well they work. There is a reason why I stick with the tried & true brands...at least until I'm forced to look elsewhere. Plugable, StarTech, and OWC all make good products with a long history. These are my main go to brands. Plus they tend to provide the most detailed technical specifications for their products so you have a better idea of what you are really getting.

@etresoft is absolutely correct....not all third party external devices are compatible with a Mac. Macs can be very picky sometimes. I discovered this many years ago which is another reason why I stay with the same tried & true brands. I very rarely have issues with them with any system, of course there are always exceptions to every rule.

UGreen - never heard of them. Kingston - not a great history with Macs.

I suggest trying something else, known to be reliable. Suggest a Samsung 870EVO or Crucial MX500 in an OWC enclosure or a Crucial X9 or X10 or a Lacie portable. Format as APFS.

Mstren509 wrote:

Its a UGreen enclosure, I bought a word garbage chinese one first and that didnt work at all so I found a name I at least recognize.

There's nothing wrong with Chinese products. UGreen is 100% Chinese.

That being said, the Mac is a tiny, tiny niche of the global electronics market. Do not expect any random component purchased from the internet to work on a Mac. Even products sold at your local "PC" electronics store have probably never been tested on a Mac. It is reasonable to expect that products sold on Apple's own site and Apple's own retail stores will work. But beyond that, you're taking chances on your own. You'll need to independently verify compatibility with major, reputable sites like Newegg.

For example, Apple sell's "LaCie" products on it site. That should be safe. Generally Samsung products will work too (but not as well you might have hoped). But beyond that, good luck!

Just in passing, Kingston + Macs doesn't have a good record of co-existing