Editing problems since upgrading to WordPress 4.9

Have a look at this page.

It might help solve the problem. If not, post back and I’ll see if I can help.

I did an followed the instructions e.g. deactivating plug-ins. I still cannot use “AddMedia”, insert links or switch to Text mode. I can write text under “Visual” and publish that.

That was fast!
Did you clear your cache between re-activating plugins and testing the problem?
If you’re using a child theme, check the functions to make sure they’re compatible.
Do you have results from the healthcheck plugin?

With the update to version 4.9, the site footers suddenly became 2 inches tall from what was 1/2 inch. Upon adjustment to customizer in control panel, footer returns to normal. Next day, site footer is gone. 4.9 update is gone too and wants to me re-update again. Re-update to 4.9, footer returns but is again giant size. Upload to site backup for 4.9 removal, sites return to normal. Next day, footer is gone, update to 4.9 is gone again, wants me to update to 4.9. Update to 4.9 third time, footer return to giant size. Next day, footer gone. 4.9 update gone again too. I can only wonder what happening at night to my websites. Using the same theme on multiple sites, each site is experiencing the same identical issue described above.

There is also a bug issue with update 4.9 disabling the control panel customizer. The site cannot be customized or repaired due to this disabling by the 4.9 update. The theme’s (Onetone theme) customizer is also disabled by the WP 4.9 update thereby rendering the sites uneditable.

Anyone have any ideas or info on this bug yet? Is anyone else reporting such errors? Is there a solution in effect? I have reviewed the 4.9 Master List posted.

@collector2017: Can you please start your own thread? Your issues don’t seem like they’re related to the OP’s issue.

I did clear my cache after re-activating plugins. We use Theme Triple K2, but this should not be a problem, because this is a back-end plugin, or? I don’t have the healthcheck plugin, unless it is build in and I don’t know how to find it.

I installed the healthcheck plug in. It just tells me what I am running, basically PHP 7.1.11, MySQL 5.7.20, and Apache 2.4.29. Clearing transients did not help. I also reinstalled WordPress version 4.9.

You can find the healthcheck plugin on the page I posted a link to previously. Before you do that, you should probably go through all the other suggestions on that page, including testing with the default wordpress theme to see if that’s causing the problem.

Could you re-visit that page and ensure that you’ve taken all the steps suggested?

I’ve been poking around the forum. It looks like they’re working on some bugs/issues similar to what you’re experiencing.
You may want to roll back to the previous version of WordPress til things get sorted. You also might want to check with your theme dev to see if there are updates for it.

Changing the theme from TripleK2 to Twenty Eleven did not work, so we may just go back to our backup before we upgraded to the newest version. I wonder if the newest version has any additional requirements on the server that the previous version did not have.

If this helps – these are the errors that appear when use F12 and go to console:
JQMIGRATE: Migrate is installed, version 1.4.1
load-scripts.php:9:542
TypeError: Language code must have format 2-3 letters and. optionally, hyphen, underscore followed by 2 more letters
mediaelement-and-player.min.js:12:4331
ReferenceError: MediaElementPlayer is not defined
[Weitere Informationen]
mediaelement-migrate.min.js:1:342
TypeError: b(…).not(…).filter(…).mediaelementplayer is not a function
[Weitere Informationen]

Adding to the above, this looks like it is a javascript problem …

We have a temorary fix. Apparently, the problem is because the backend was not specifically set to German (Settings) when the language of WP4.9 installation is also German. Apparently, the current WP version does not tolerate these to be set differently. I think this is a bug, not a feature, and should be fixed.

Please do check if any errors in console if yes then attach image here . ??

Here is the info als plain text (again, I posted it above) when the language of the user is not German (Deutsch) but rather the web language. This error did not appear anymore after changing the language from the default (web language) to German:

JQMIGRATE: Migrate is installed, version 1.4.1
load-scripts.php:9:542
TypeError: Language code must have format 2-3 letters and. optionally, hyphen, underscore followed by 2 more letters
mediaelement-and-player.min.js:12:4331
ReferenceError: MediaElementPlayer is not defined
[Weitere Informationen]
mediaelement-migrate.min.js:1:342
TypeError: b(…).not(…).filter(…).mediaelementplayer is not a function
[Weitere Informationen]