I made the Core Update from 7.17 onto 7.18. I just ran update.php, no errors were thrown.
However when I edit/create one of my content types, I saw the following.

Warning: Invalid argument supplied for foreach() in form_type_checkboxes_value() (line 2288 of ../drupal/includes/form.inc).

I have no idea, why this error appears. Doesn't seem to be much of a problem but I wanted to point it out.
I have uninstalled several modules, but the warning doesn't disappear. I have no starting point for a solution.

Comments

ctmattice1’s picture

ctmattice1 commented

Does this happen with just quotes content or for any content on the site?

Anonymous’s picture

Anonymous (not verified) commented

For any content... blog, basic page, webform, faq, forum, own types, etc.

The update onto drupal 7.19 has brought no improvement.
How can I find out what module causes these problems? The best way for that?

Anonymous’s picture

Anonymous (not verified) commented
Status: Active » Closed (duplicate)

Ok, i figure out, that the Content Optimizer Moduel causes the problem. I open a bug report there.