Database update won't work

I have same exact issue Jackyv. Have you been able to resolve your problem?

Same issue on a website I run for a friend.

Already tried disabling all plug-ins and forcing default theme through FTP, but no luck.

Same issue on one of the sites I manage, but not the other. From past threads I’m thinking this issue may be related to the fact that my theme isn’t compatible with the upgrade yet. I’m restoring my backup with the previous version until I have the time to fool around with it or a fix is found.

That’s the only answer I got till now:
https://core.trac.www.ads-software.com/ticket/36511#comment:2

And I’m not exactly sure what it means.

Anyone?

Solved the issue, only took me like 5 hours.

Long story short, you need SSH access so you can use WP-CLI, then you can upgrade the database through command line

the magic words are:

wp core update-db

these pages helped me

https://community.1and1.com/broken-website-after-upgrade-on-wordpress-4-5/
https://community.1and1.com/wp-cli-how/
https://support.hostgator.com/articles/hosting-guide/lets-get-started/how-do-i-get-and-use-ssh-access#connect
https://wp-cli.org/commands/

Can you dumb it down at all?

@aslug
That did it!
Thank you so much!