So after updating to WP 5.3 I can no longer use the file upload to choose files to add. I get the following error:

Uncaught TypeError: Cannot convert undefined or null to object
    at g.cleanup (backbone.min.js:1)

Error in console:

How it shows when I try to choose an image:

I have the Classic Editor plugin installed so I can use it the classic way. I have disabled all other unnecessary plugins but the problem still persists. It's only happened since the new WP core update to 5.3 yesterday.

Any ideas what's going on here?

So after updating to WP 5.3 I can no longer use the file upload to choose files to add. I get the following error:

Uncaught TypeError: Cannot convert undefined or null to object
    at g.cleanup (backbone.min.js:1)

Error in console:

How it shows when I try to choose an image:

I have the Classic Editor plugin installed so I can use it the classic way. I have disabled all other unnecessary plugins but the problem still persists. It's only happened since the new WP core update to 5.3 yesterday.

Any ideas what's going on here?

• plugins
• media-library
• core

• Having the same issue, glad I'm not alone. – Arda Commented Nov 15, 2019 at 11:23

3 Answers 3

I had the same problem. In my case it was the Enhanced Media Library plugin, which looks as though it has not been updated in some time. I deactivated it, and all is good.

Right, so what worked for me was upgrading my PHP version to 7.2 and that did the job.

I was using 7.0 before.

My problem was with ŧhe Enhanced Media Library plugin and this solution worked for me https://wordpress/support/topic/quick-fix-for-upload-breakage-after-wp-5-3/