Apple Bobber wrote:
I'm having the exact same issue. I've been kind of lax upgrading my OS after quite a few prompts the last few months as I've not been close to my NAS drive to run my usual Time Machine backups.
Don't be lax with backups when using an SSD since an SSD can fail at any time without any warning signs. Plus with the USB-C Macs you could easily lose access to the data on the Mac if anything happens to the Logic Board since the SSDs are soldered to the Logic Boards on most Macs these days and there is very little chance of recovering data from them. In addition it is impossible to recover accidentally deleted data from an SSD after the Trash has been emptied.
tested out DriveDX and it flags a SMART error on that. Really thought Disk Utility would have notified me but I'm now resigned to thinking there is a real hardware problem. I guess the only thing is to go to an Apple store to replace it?
While most times a drive is reporting a "SMART failure" with DriveDx it means the drive is bad, but not all SMART Failures may be real failures especially with SSDs. Feel free to post a DriveDx report here using the "Additional Text" icon which looks like a piece of paper. DriveDx and other similar apps still tend to interpret drive health reports as if the drive is a hard drive which can be Ok most times, but there are some occasions when this will result in throwing away a good SSD (I always manually interpret the health report to confirm the failure is real).
Unfortunately Apple doesn't do a whole lot with the SMART monitoring features of drives. Only if the drive itself tells the OS the SMART status has failed will macOS silently alert the user with a red notification of the status change in Disk Utility. This only happens when the drive failure is severe (I've only seen it happen twice, although I've replaced thousands of drives on Macs where the SMART health report showed as having issues, but not an actual "Failing" status since most drives become unusable long before the "Failing" state is reached). The Apple Diagnostics will utilize a little bit more of the drive's SMART health monitoring features, but usually only by using the drive's own internal SMART selftest feature (unfortunately not available on SSDs on USB-C Macs).
As for Disk Utility and First Aid, this only checks the integrity of the file system. First Aid does not check the physical health of the driver.
I have a clone of my machine on an external SSD made with Carbon Copy Cloner (similar to SuperDuper!)... Can I install the new OS onto there and run from that until I replace my MacBook SSD to then copy back?
It depends how you made the clone with CCC. If the clone drive is bootable, then you can use it as an external boot drive. FYI, when cloning a macOS 11.x+ boot drive with CCC, you must take extra steps to make a clone drive bootable.