Message “There was an invalid entry on the form. Please try again.”

I am getting the message “There was an invalid entry on the form. Please try again.” when trying to save changed to files, specifically deleting or reordering files from an item. There is no corresponding error in the error log.

Does this only happen with files? Not with changes to metadata?
What version of Classic are you running?

Classic Version 2.6.1, Metadata too. Also with more testing this error is only occurring on some items, not all.

Can you post the contents of your “System Information” page? (It’s linked at the bottom of all admin pages.) And also a screenshot of the error message?

We are now also having an issue of items not loading and users getting “No preview available”. I do not know if this is somehow related.

Is the “error on the form” problem consistent on other browsers or computers? I see your screenshot is from Mobile Safari, but does the same thing happen in Firefox or Chrome, and on a laptop or desktop?

I have tried in in Chrome, Firefox and IE on desktop as well as on mobile

With some extra information about the problem items, it looks like the problem here only occurs on items with lots of uploaded files, in the hundreds of files.

I believe you’re hitting the PHP limit on how many variables can be uploaded from a single page. This is controlled by the php.ini setting max_input_vars, and it defaults to 1000. Increasing this value should resolve the issue.

I have increased the max_input_vars and am still getting the error

If you increased that in the php.ini file, you’d have to restart PHP and/or Apache for the change to take effect. Have you done that?

If you have, just a double-check: does the problem happen only on items with lots and lots of attached files? If so, I’m fairly certain that max_input_vars is the appropriate setting to be looking at.

I forgot to restart, it seems to be working, other than on the items where the issue started, but I can just delete that and start fresh. Thank you