My MBP 2019 with i9T2Chip was working with a DualBoot Monterey (on MacintoshHD) and Ventura (on other partition) and after installing the latest Ventura Update on that partition, the main Monterey Partition won't start up, and as a dive in shows, figures now with Sonoma 14.5 SystemVersion.plist
I can't figure out what happened, 4 days ago I updated Monterey to 12.7.5, today I booted, read some news during breakfast and then switched partition to update the Ventura OS to it's latest update. After trying to switch back to monterey the monterey partition is in an endless boot-loop.
It forwards a little then the screen flickers, the mouse appears, the boot bar jumps to the end and then black screen and later showing recovery asking for internet conection to verify the disk.
Fortunately the Ventura Partition allows still to boot, so I started up, Diskutilities did not help, NVRAM reset, SMC reset, startup in diagnose mode, all with no result.
I tried to reinstall Monterey over internet: preflight error 21, made a usb installer, chose monterey partition with error "Cannot downgrade"...
That made me wonder: why downgrade? it's the same system version, but the startup disk menu indicated 14.5 for the monterey partition...
So I deep dived into /System/Library/CoreServices/SystemVersion.plist and there it was the monterey SystemVersion became somehow Sonoma, even if sonoma is not installed, and was not installed nor installing... It was a clean reboot from Monterey into Sonoma.
My only guess is that the Ventura update messed up something, but how and why???? no clue.
Can anyone help me on how I could reset the systemVersion to Monterey so that I can make a clean install? I have a one month old TimeMachine Backup, and off course I could upgrade to sonoma, but I'd prefere to have Monterey or Ventura on that Partition, as the other one is for DAW compatibility tests...
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>BuildID</key>
<string>4805124E-0C37-11EF-BC27-82EAA8E0F66E</string>
<key>ProductBuildVersion</key>
<string>23F79</string>
<key>ProductCopyright</key>
<string>1983-2024 Apple Inc.</string>
<key>ProductName</key>
<string>macOS</string>
<key>ProductUserVisibleVersion</key>
<string>14.5</string>
<key>ProductVersion</key>
<string>14.5</string>
<key>iOSSupportVersion</key>
<string>17.5</string>
</dict>
</plist>