"Clean" Update from High Sierra to Big Sur (MB Pro Late 2013)

[DigitalDIY]

Hello guys,

i have been reading in this forum for quite some time and now I came to ask you for help.

My situation is the following:

Me and my dad want to share his MBP late 2013. He did not update the OS for a few years, so it is 10.13.6 High Sierra right now.
I would like to upgrade to Big Sur (especially because I can't download Apps from the Appstore because they require a newer version).
It seems like I can't simply update via the system because I get the following error: invalid key order (63) did 4133676 / oxid 0
Object map is invalid.
Everything is backed up via time machine. And all relevant files are uploaded to iCloud.
After some research I find it best to wipe the OS and then go on to install Big Sur.

And here comes my question:
Right now, there are two user accounts on the MB (one for my dad and one for me).
Is there a way to wipe everything and restore installed apps, documents etc. BUT with the new OS?
If I would install a backup from time machine it would just put on a copy with High Sierra, is that correct?

Would love to hear a solution from you wise guys of the Macrumors forum!!

 

[Brian33]

And here comes my question:
Right now, there are two user accounts on the MB (one for my dad and one for me).
Is there a way to wipe everything and restore installed apps, documents etc. BUT with the new OS?
If I would install a backup from time machine it would just put on a copy with High Sierra, is that correct?

This is exactly what Migration Assistant is for -- copying applications, user accounts, and settings (but not the OS files) from a previously backed up system. Assuming you have a good Time Machine and/or cloned backup (be sure you do!), you can wipe the internal storage and install a newer OS. During the installation process it will ask you if you want to "migrate users and data" (or some similar wording) from a backup.

If you answer yes, you can attach your external backup drive. Migration Assistant will "chug away" for awhile, analyzing its contents, then a window will come up asking what you want to migrate. Going from memory, you can check/uncheck categories like system settings, applications, and individual user accounts with their data.

Alternatively, you could answer No, and run 'Migration Assistant.app' later (it's in the normal Applications folder). If you choose this course, when the installation process prompts you to create the "first" admin user account, I would use a new, temporary, name (NOT one of the two account names on the backup drive). When the installation is done, you can log in with the new admin account and run Migration Assistant. After testing for the successful migration of your old accounts, you can log into one of them and delete the "temporary" admin.

Note: I'm still on Mojave and have never installed Big Sur, but I'm pretty sure that Big Sur Migration Assistant still works the same way.