If you read my previous post I mentioned that Drupal v7.50 has it's apparent difficulties. I spoke of the issue of the consequences of physically uninstalling modules without removing them from the database. Now I will talk some about the other error that surfaces with the upgrade to Drupal 7.50.
That error is:
Funny thing happened with Drupal 7.50, errors started appearing that I had no clue about. It started telling me about modules not being where they were supposed to be and about a utf-8 not being enabled.
One of the errors received was:
The following module is missing from the file system: <em class="placeholder">plup</em>. In order to fix this, put the module back in its original location. For more information, see <a href="https://www.drupal.org/node/2487215">the documentation page</a>. bootstrap.inc:1128.