Kareem7md wrote:
Questions:
• What macOS-level issue could cause an external SSD to be completely undetected while working on another laptop?
First, great start at troubleshooting things so far!
Unfortunately Safe Mode is not as clear cut as it used to be according to a respected & very knowledge forum contributor. IIRC, there are now Finder extensions which remain active in Safe Mode.
• Are there any safe diagnostics or resets I can try without risking data loss?
• Could this be related to USB permissions, kernel extensions, or macOS security settings?
Since Disk Utility gets stuck when trying to access the external SSD, then I would suspect a hardware issue of some sort since Safe Mode didn't help. Have you tried using each of the other USB ports on your Mac....if a laptop, then especially try the ports on the other side.
There is still a chance of a file system or partition issue on that external SSD. You neglected to mention details about the other laptop which can access this SSD including the exact model and version of OS on it. Plus you neglected to mention the exact model of this external SSD and file system used on it and what computer/OS was used to originally erase/format it, or whether the file system is from the factory.
If you have a USB hub, is it a powered hub? And did you try using this SSD along with this hub?
To eliminate all software issues, try booting into Recovery Mode and see if Disk Utility is able to see the external SSD. This will tell us if Safe Mode was insufficient here.
Are you having any issues with any other USB devices connected to this Mac?
Once I know the exact model and OS used on the other laptop which could access this SSD, then I may be able to provide you with a method to check that SSD's health. Unfortunately if Disk Utility is getting stuck, then it is unlikely DriveDx (as suggested by @D.I. Johnson) will be able to see the physical SSD because Disk Utility will likely be hogging all communications with that drive. If your other laptop is a Mac, then that could be used to check the health of the SSD....post the complete DriveDx text report here using the "Additional Text" icon which looks like a piece of paper on the forum editing toolbar.
It may be worthwhile to run the third party app EtreCheck and post the complete report here so we can examine it for possible clues. It is certainly possible there could be an issue with third party software that is interfering even though Safe Mode did not make a difference. Some anti-virus apps, cleaning/optimizer apps, and third party security software may make system level changes that remain even when those apps are not currently active & loaded.
How to use the Add Text Feature When Posting an EtreCheck Report - Apple Community
I still think this is more likely a hardware issue of some sort, or a file system issue on the external SSD. Or possibly even a compatibility issue with the external SSD and Apple hardware/software, but it is still hard to say for certain at this time.
I’m intentionally avoiding erasing, initializing, or reformatting the drive.
We are not there yet. Does this mean you don't have a backup of the data stored on this SSD?
If so, then use your other laptop to make at least one backup copy of the data stored on this SSD. People should always have frequent & regular backups of external media (including the cloud) if it contains important & unique data.......and your computers should also have frequent & regular backups. It is nearly impossible to recover data from devices these days, even if they are Hard Drives. If it is even possible, then it will be expensive.
