Disk Utility doesn't seem to be aware of the drives on my system until I open it , it then takes about 90 seconds to scan in OSX Monterey

gitarman4 wrote:

So it would seem that my M1 iMac is not running well.

It takes about 20/30 second to boot up and as I say, Disk utility is very slow to load the disks.

Slowness can be caused by a number of different things.

(excess user login items, a hung or failed process, third party AV and cleaning junkware)

Run EtreCheck Pro on your iMac. https://etrecheck.com

Then post back with your Report. How to use the Add Text Feature When Post… - Apple Community

Okay I have to take back part of what I said. My Intel iMac which has three HDD drives plugged into a hub is rather slow. My M1 MacBook Air which has only one portable SSD plugged into an Apple multi-port adapter is basically instant on.

In addition to what others have mentioned, the speed can be affected by the health of the drive, and the health/condition of the partition and file system on the drive. Are your drives getting power from the Mac or do they have their own power supplies or get extra power from a powered USB3 hub or dock? Are you using the proper cables and adapters? Not all USB-C cables work at USB3 speeds such as the Apple charging cable supplied with the USB-C model Apple laptops.

Other externally connected devices may also play a role in how things work together. macOS 12.x Monterey is known to have some compatibility issues with USB3 drives although macOS 12.1 was supposed to have resolved most of those issues. It appears users with a Wacom tablet still have issues with USB3 drives even with the latest version of Monterey.

There are a lot of other things which could contribute, but you get my drift that you may have to do some investigating and experimentation.

FWIW, I think that's normal. I see the same thing although I'm not sure it takes 90 seconds. It is quite a bit slower. No idea why.

Well, it's slower on Intel Macs as well. The only thing I can think of is since the APFS switch it does more extensive checking. Don't quote me on that. 😎

I just checked my 512GB SSD M1 iMac with a 1TB USB-2 external HDD and the display was instantaneous.

Do you have any software installed which may impact on performance, such as anti-virus / clean-up apps?

Hmm, FWIW, Disk Utility loads and populates instantly with my 2017 iMac 27 inch with 1 TB SSD & 4 TB external HD.