Data Recovery of an Internal SSD that keeps ejecting

It sounds like the SSD is failing.

I think you need to copy small amounts of data & let the SSD rest a bit. Rinse & repeat.

If the data is important, then I highly recommend you contact a professional data recovery service since you may be making the SSD failure worse.

I recently had an SSD with similar issues on a Windows laptop where the user needed me to recover some data that had not gotten backed up. I had to do a lot of fiddling to get several GBs of data, but was able to get the whole user folder as well after some more fiddling & dumb luck. I only pursued it out of curiosity to better understand the SSD failure behavior at that point since I had never seen an SSD with such odd behavior (I knew it was a bad SSD).

FYI, people should always have frequent and regular backups of their computer and all external media (including the cloud) which contains important & unique data. There are a lot more new ways to permanently lose access to the data on the internal SSD of the recent Macs due to all of the hardware, software, and security changes. This is just a normal SSD failure which as you are discovering is very difficult to retrieve data from it. There literally is nothing you can do except get lucky to access & transfer the data....seems like you may have used up your luck to retrieve that one folder with your most critical items.

CuriousGoose wrote:

I have no problem having full access to the internal SSD when it isn't ejected. I see all the files and folders. My Mac can stay turned on for quite a while, and the SSD doesn't eject. It's only when I try copying data from it that it ejects.

Exactly. That is one of the common ways an SSD fails.

I cannot rinse & repeat, because that would take dozens of boots... and it's not promised that each copying attempt will be 15GB in size. It's just not a viable option.

Exactly, that is the only way. I had to do that to retrieve a few GBs of data from someone's Windows PC recently.

Or you can contact an expensive professional data recovery service to attempt to recover the data.

These are your only two choices if you do not have a backup of your data.

I haven't tried any Terminal repair commands, as I wanted to make an image first... but clearly that's not going well at all.

On a Mac, the only way to make a low level image is by using the command line. I'm not aware of any macOS third party utilities which will do so. However, most likely you will encounter the same disconnect issue because the SSD is FAILING. When that happens you will be starting over with the imaging process since there is only one command line utility I am aware of which can resume an interrupted image process, but their is no precompiled binary version of it for macOS. I've always used a Linux boot disk to perform the raw low level block imaging.

I highly doubt you are going to be successful at recovering all of the data even with a professional data recovery service.