Drupal - How can you remove the edit lock on a node?
Did you use the back button to get to your edit page? Have you tried manually going to the node and clicking the edit tab again to see if it reoccurs?
This message is caused when either (1) two users access the edit page and one user saves changes before the other user gets a chance or (2) when a user edits content, saves it, and clicks the back button to get back to the edit page.
https://obrienmedia.co.uk/kb/drupal-website-management/avoiding-the-the-content-on-this-page-has-either-been-modified-by
Are there other users signed in? When all else fails (or rather the first step of troubleshooting always) Flush all cache. Clear your browser cache. Close your browser out. Re-open your browser. Attempt to recreate problem. Is it still happening?
I had the same problem on an international site and here it was the "Administration Language Module" that caused the troubles. JFYI.
If the problem is related to two users editing the same record (node), it can be related to max_input_vars in your php.ini
There are two solutions to solve the problem (I recommend trying both of them):
- Edit phpi.ini and increase max_input_vars (find max_input_vars = ... and increase it). php.ini can be found in different locations for example in an ubuntu conventional setup it can be at /etc/php5/apache2/php.ini
- Clear cache (depend on your browser this is a pretty easy routine and you already do not know it, just google it).