When i try to set the url of a page in wordpress (4.2) it keeps apending -2 to the end of the url, i guess its becuase this ulr already exists, but i checked and it dosnt, although at one time it did but that page has since been deleted. Any idea how i can use the url i want and get it to stop apending -2 ?
This is what im seeing the wp-admin dashboard when trying to change the url :
The edit box : 
Once i click OK :
I know this topic is old, but I was having the same issue, and none of the suggested fixes worked.
I didn’t have any pages still in trash. I didn’t have a category with the same name as my page. I didn’t have another page with the same name. So I did something crazy. WP was trying to name my page as page-2, so I went to mywebsite.com/page to see what happened.
A page with a single photo popped up. I had a PHOTO with the same name as the page, and WP media manager gives photos permalinks based on the file name! Fix was to rename the photo (still keeping SEO in mind), and using the permalink editor for the page. TAH DAH! Like magic, it worked