This message in the Pages database settings tends to alert and confuse users.
But don’t worry about it. It’s not an error and usually not something you need to fix.
Background: By default, a Pages database has one category. You can then either turn categories or on or off. This changes how the database is displayed on the front end. (For example: Without categories, there will be no category listing page.) Once you start to add more categories, the message shown above will appear. It is just telling you, that you cannot turn off categories anymore.
If you still want to …
- move all records into one category
- delete all but this one category
Then the message will disappear and you can turn categories off again.
Edited by admin