To start i'm a music produce since 6 years and i bot my Imac 4 years ago and use it for my production. I don't have a TM backup because my external drive, 1TB, is permanently rejected by the mac i don#t know for what reason. Image if i loose all my data !!! This will be my last Apple computer and will go back to Windows as they don't have this mountain of issues when they release a "new SAFE OS update" ...!!!
i'm trying since one week to have a successful installation of macOS Big Sur 11.4 on my Imac late 2015 with Intel i5 processor and 1TB HDD. According to Apple my mac should be ready for the new OS. Since months i have an error while trying to download the update. And since one week i had different error:
First: "An error occurred while installing the selected updates macos big sur"
..then "An error occurred applying the software update in macos big sur"
..then "An error occurred preparing the software update"
.. and since yesterday when i reboot(normal start) the mac i have a black screen with a prohibition sign. and this is what it means: "A prohibitory symbol, which looks like a circle with a line or slash through it, means that your startup disk contains a Mac operating system, but it's not a version or build of macOS that your Mac can use." !!
i tried everything i could find on support.apple.com ... Safe mode couldn't start, it an endless loop till release the Shift key.. reset SMC and NVRAM/PRAM .. Diagnostics gave error PPM002 but i can see my disks on the terminal and in Disk Utility. DiskUtility says disks are OK .. i did the Internet recovery many times (opt+cmd+r and shit+opt+cmd+r), but it ends with same error after hours (error applying the software update). It shows me at the beginning 2 hours and 19 minutes left than it goes up .. one time 29 hours .. than 35 hours .. and today it went up to 50 hours .. and i know it will end with the same error .. i reinstalled big sur on external drive with 1TB, ended also with error.
But since yesterday my file system changed. It is not like in Catalina .. i can see it using Terminal in recovery mode. but my user folder is gone. My Macintosh HD still showing 169 GB but when i check the file system with terminal i see empty files ... Users/ contains only Shared/ folder ... Users/ is now in /system/Volume/Data/Users. If i'm not wrong, before it was in /Volumes/Macintosh HD/Users/MyUser/. I have also two Volumes, a Macintosh HD (with 57 KB used) and Macintosh HD - Data (with 162 GB used).
For today i will make a bootable USB with macOS 11.4 and try to boot from external drive .. i saw that people did it without losing data .. then i want to try the Target Disc Mode and therefore i have to buy a thunderbolt 3 cable and bring my imac to a friend's place that has Big Sur working ... else i will try a Catalina downgrade and go buy me PC.
My worst experience with a system update.
