Login sometimes quick... other times very slow.

Actually... What I said about my solution isn't right.

The problem being intermittent makes this hard to locate

I have now pretty certainly I know what it is.

I have an M.2 SSD in an Orico enclosure. When that is attached, it can occasionally cause slowness when I log in.

Theoretically the disks are mounted by then.. so its not a mount. (In fact I know the disks are mounted because if I leave terminal open and login... I can make unix commands and mount does show the external disk as mounted).

This manifests itself as the desktop taking ages to appear, and seems to have stalled. The disks do NOT appear on the desktop (mostly), and even when they do you cannot double click them (any of them, including the OS internal disk).

Apps open (if previously open), but then they have spinning icons (most of the time)... occasionally they appear functional as long as you don't tdo anything too fruity. Unix Terminal behaves as long as you don't try to navigate to the offending Volume).

The disks appear ok as far as Disk Utility is concerned.

Spotlight appears to be stuck indexing (its not a spotlight problem though.. because even if I disable spotlight this still happens - again intermittently).

BUT if I just pull out the thunderbolt cable connecting the enclosure... boom the desktop appears and the Mac runs normally. I can then replug in the USB enclosure, and its all fine (bar the message about not having correctly ejected the disk).

So, it's something to do with access to the disk connected on the thunderbolt port. The disk access light is blinking very rapidly when its doing this.. suggesting access.. but whatever its doing its doing it really slowly and it's blocking everything else.

I am getting another (different company) enclosure today... and I'll be able to narrow it down if this one works.

However if the new one behaves the same, then it suggest the OS is performing some kind of blocking activity that prevents any other IO until that has completed whatever its doing.

Right. So it was the enclosure. No doubt about it.

The failing enclosure is an Orico M.2 SSD Enclosure (M208C3-U4).

It just doesn't play nice with Mac OS. (at least on Intel, can't speak for M series processor based Macs).

If you're tempted to buy one of these to house an M.2 ssd. don't. As of now (unless there is some kind of firmware/hardware change) it will not work. You will tear your hair out and likely go as bald as Telly Savalas, and not be anywhere near as cool.

The SSD enclosure that did work was an ACASIS NVMe M.2 SSD enclosure (TBU401E)

Wow, that was a painful 2 weeks, as I thought it was something I had done in the migration from the Older Mac to this one.

Certain apps (which try to load - since they were started at the time I last logged off / shutdown ) also seem to cause problems. For example iStatistica Pro.. that hangs occasionally on login (if its opening because it was open at the end of the last login) - That too seems to affect the rendering of desktop (the disks). If I force quit that.. the desktop loads. Could be a Ventura issue too.

I think I have understood the problem.

This Mac Pro is new to me (Previously loved by someone else).

This issue really stems from how the migration brought what it could over.

Some of it it couldn't do (because the internal drive to this Mac is too small).

I had placed those folders onto an external drive and I made them my Home.

This caused no end of permission problems that on the surface looked ok.

Disk Utility doesn't seem to care a jot about fixing permissions on external drives EVEN IF they are legitimate homes.

With quite a lot of mucking about. I have managed to create symlinks in such a way that Apple in its wisdom will not be able overwrite when iCloud synching occurs.

It would be HUGELY beneficial if Apple recognised that NOT EVERYONE will buy a Mac with a sufficiently large enough hard drive WELDED into the computer in such a way as to make upgrading deeply problematic.

But of course they wouldn't be able to wring every penny out of us in any other way.

I won't bore you with the details of how I managed to wrangle this on to the computer, lots of Unix / terminal malarkey that can be found by trawling the web.

Anyway this has now been solved, my logins work as I would expect and I have my data on the external drive.

Thanks for coming back to me so quickly though. Much appreciated.

I will say I miss Catalina, Ventura gets my grits something rotten.

Sorry to keep a running monologue going here. I just hope this helps someone else.

sadly the success with the new enclosure was a false dawn.

now that I have trawled all sources on the internet, it’s becoming clear Ventura is riddled with bugs around handling external drives. I think I have no option but to downgrade to the OS this machine shipped with since I have no Monterey backup. What an enormous pain.

Shame on you Apple for foisting this steaming pile onto us.