I use a Sandisk 1TB external SSD for my photographs. I

In addition to the wonderful suggestions @Mr Hoffman offers try running Disk Utility First Aid on the SSD's volume and even on the physical drive. You may need to click on "View" and select "Show All Devices" before the physical drive appears in the left pane of Disk Utility. I recently had a Mac where the file system was having errors even though Disk Utility ignored them and showed everything was "OK", but those ignored errors prevented the laptop from booting into Internet Recovery Mode and even crashed another Mac when trying to connect the laptop to it in Target Disk Mode. A file system issue can have the behavior you are describing.

Do you know what file system was being used on the external SSD?

You definitely need to backup your computer and any external drives which contain important & unique data since an SSD can fail at any time without any warning signs.

I don't see anywhere that you have done the simple fixes for this type of issue.

I would try, unplug and restart the computer, pram reset, smc reset, safe mode, and trying the SSD on another computer. Sometimes the basic fixes will work.

Got backups of that data? If not, go get those right now.

Which model SSD?

Current vendor firmware loaded?

What do the Sandisk diagnostic tools show?

If Sandisk diagnostic lacks tools for their external SSD devices on macOS, try DriveDX.

Any add-on anti-malware apps, add-in anti-virus apps, or add-on cleaner apps around?

Download and run and post the output from EtreCheck here. Open a new reply here and then press the button that looks like a printed page to get a text input box big enough to paste the hardware and software configuration report directly here.

I don't see anything in those reports that concern me. There is one attribute with the Sandisk SSD that I'm not familiar with (#167) and I couldn't find any information on it as it must be unique to Sandisk. I also couldn't locate what the latest firmware is for your Sandisk drive. The Sandisk/WD site is not the best since searching for the product model doesn't reveal any results on the support site.

Run Disk Utility First Aid again on the SanDisk drive and look at the Details of the scan. Are any errors listed that were not repaired (even though the overall scan says "Ok")? What file system is being used on the external drive? I don't see the file system listed on the EtreCheck report. It might be worthwhile to backup this Sandisk drive and completely erase the physical drive and test it with a fresh partition & file system.

Do you have another external drive you can use to test with the laptop (an SSD would be best, but even a hard drive may prove useful to verify the ports on the Mac)?

Since the laptop doesn't appear to have any offending software I think you will need to deal with Sandisk/WD and official Apple Support channels for resolving the issue. Good luck with that as both parties will point their fingers at the other one. Of course Apple will insist you perform a clean install of macOS for testing purposes (erase the physical drive before reinstalling macOS & without restoring or migrating from a backup).

Kernel panics are the concern in that EtreCheck report.

Probably related to the storage, though could be some other issue with hardware or with Catalina.

Find the most recent panic in the following location and post that here: /Library/Logs/DiagnosticReports

Reading panics can be dicy, unfortunately.

We can (usually) tell where to look and what immediately happened, but not necessarily what provoked the crash.

I'd be inclined to swap in a different external storage device, and see if that too crashed.

What’s in the EtreCheck report and the DriveDx report all looks fine, Apple’s ongoing issues around accessing attachments here in ASC aside.

Enable Full Drive Access for the crash reports, and re-run the EtreCheck report. Maybe that shows more?

The SanDisk website does not list the current firmware for X600 anywhere obvious, and the tools are seemingly only for Windows, and the major firmware tool lists internal-only SSD support, and the embedded search engine over there at SanDisk prolly couldn’t find itself if you spotted it the URL.

For those of us having “fun” getting at the attachments, firmware X61110RL is loaded, and thr SSD model is SD9SN8W1T00.

(FWIW Disk Utility can also be used for at least some SanDisk SSDs.)

Please post the entire EtreCheck report.

Open a reply here.

Then press the button that looks like a printed page.

That will open up an input box big enough for lots of text.

Then paste THE ENTIRE report into that text input box.

Thank You.

You do not need the “power users” package. Not yet. If at all.

Adobe licensing is at the top of that, but that app is quite possibly (probably?) a bystander. Something has corrupted the kernel. Though I don’t think it’s an issue with Adobe, do update that to current if not already. Beyond calling the folks at Apple Support, I don’t know what else to suggest.

Finger-pointing discussions aside, crashing secondary to a storage device is generally bad.

The crash logs here (if any) might show some info, there.

That’s the DriveDx report...