For those experiencing the WordPress 5.2 breaks admin issue, restoring /wp-admin, /wp-includes, and wp-settings.php has helped get the admin system back online.
If you don’t have a backup, you can pull these from the original 5.1.1 WordPress installer package. For safety’s sake, I’d rename each instead of replacing — e.g. rename /wp-admin to /wp-admin_5.2, etc.
Out of a few dozen websites I manually upgraded, only one experienced this issue, but based on others’ experiences, it looks like it’s something plenty of people are seeing. After updating to 5.2, the website remained online, but the wp-admin panel was inaccessible and you’d get an err_too_many_redirects error.
Just thought I’d put out a way that got the WordPress admin back online.
Dean
I am a Software Developer, System Administrator, and consignment software specialist. I currently manage hundreds of consignment workstations, point of sale systems, and database servers all across North America and I am the developer of Peeps' Software, Peeps2Go, and Peeps' Consignor Login for iOS and Android. I've been helping consignment & resale store-owners since 2003. I started The Computer Peeps in February of 2010. Peeps' Software launched in 2016 and is now on hundreds of systems all across North America. I have successfully converted dozens of stores from all of the major consignment software systems. After 20 years of working with consignment stores, I understand the unique challenges consignment & resale store-owners face. From electrical issues in old buildings or strip malls, to advocating for them when their old consignment software keeps crashing.