Problem After Upgrading to Monterey on iMac Pro

I think the reinstall may be necessary. That said, the installation should not take 11 hours. My download took around an hour or so and the installation took another hour with multiple automatic restarts. I'll bet that you are using a Wi-Fi to do the download. Don't. It is too slow and these files are too large for it. Plus, the file can often get corrupted and either won't load or it will have problems (as you have). Instead, use a wired Ethernet connection, at least for these downloads. If necessary, temporarily move your computer. Otherwise you may have to do multiple downloads until you get a clean one that works. Not all Wi-Fi is bad, but many of them are not up to the job for these downloads.

I know someone that has Monterey 12.0.1 installed on their iMac Pro and is working without a problem. So it is not a general issue with all iMac Pros.

Sounds more like you have some corrupted preference file somewhere or perhaps a menu bar item from some app that is not compatible with Monterey and is blocking the menu bar from loading which is evidenced clearly by the fact hat all is fine in safe mode since it blocks all 3rd party drivers, extensions, and 3rd party apps that load on booting. So, you need to see which one is the culprit by disabling all the aforementioned items and add them one by one until the error occurs.

Also, for future reference, what I do when a macOS upgrade has completed downloading, quit the installer and I save a copy of the installer somewhere and also make a USB bootable installer in case the odd situation occurs so I don't have to download again.

richardfromphelps wrote:

Sounds to me like a patch is in the works from Apple

Don't think so. I have Monterey installed on 4 different Macs including an iMac Pro and none do what you describe.

You don't happen to have "Automatically hide and show the menu bar on desktop" checked in System Preferences > Dock & Menu Bar?

A patch from Apple will not resolve your slow download problem. Based on your description, you have a serious internet problem. I would first, try resetting your modem to see if that helps. If not, contact your internet provider for assistance. They can be very helpful.

I am trying to upgrade to Monterey on my MacBook Pro. The download went fine (apparently), but the installation totally stalls, multiple times on "less than one minute to go." Right now, my MacBook is totally stalled, barely starts to boot. Starting in Safe Mode gets me nowhere. Where do I take it from here?