I am booting from an external Sandisk Extreme SSD on an [EDIT] 2015 iMac. After updating to Monterray it now takes about 6-8 minutes to boot and runs very slow, with lots of delays, lags, and beach balls. It’s verging on the unusable. According to iStat Menus its not a memory issue.
A Google finds others with this and suggests it may be related to external boot drives. But is it just a case of waiting until the next upgrade for apple to fix it? t hasn’t happened on My M1 Air.
When you say it hasn’t happened on my M1 MacBook. Do you also boot from external drive on the M1?
Sorry, no, I should have made that clear
Happens in Safe Mode too.
On its now in safe mode. Totally unusable, lag between keyboard and screen
I saw a post on another forum saying external SSDs are running much slower than they should be on Monteray. They had benchmarks to prove their point. Then there are people saying external SSDs aren’t working at all on certain M1 Macs with Monteray. Point is, it sounds like there might be some bugs out there in this area.
I did notice my weekly back ups to my external SSD have been slower than normal on my Intel iMac since updating to Monteray.
So after. Cmd-r-p to reset things I got the ‘no entry’ prohibited sign.
An odd thing is that if I then boot into recovery mode, I get the option to restore Big Sur, not Monterrey. If I try to restore time machine backup it says it can’t and must be done by migration mode.
I’ve hit the limit of my knowledge here.
Think I will have to restore to Big Sur and hope iCloud Drive restore my latest files.
Regarding reinstalling from Recovery Mode:
On an Intel-based Mac, if you use Shift-Option-Command-R during startup, you’re offered the macOS that came with your Mac, or the closest version still available. If you use Option-Command-R during startup, in most cases you’re offered the latest macOS that is compatible with your Mac. Otherwise you’re offered the macOS that came with your Mac, or the closest version still available.
How to reinstall macOS - Apple Support
Update: It wouldn’t restore to Big Sur. I can’t remember the exact details (OK I’d had a few wines!) but it did one more very long boot into Monterray and I have to say it seems a lot better! Whilst in recovery mode I did a repair in Disk Utility - maybe that helped.
Update: seem pretty back to normal now. Only other thing I can think of is I unplugged and reconnected external SSD at some point.
EDIT: No its not! Slowed down and took about 30 mins to boot to restart. Seems OK on restart though.