sql server 2008 management studio says “Saving changes is not permitted…”

Sql Server 2008 Management Studio
“Saving changes is not permitted. The changes you have made require the following tables to be dropped and re-created. You have either made changes to a table that can’t be re-created or enabled the option Prevent saving changes that require the table to be re-created.”
Tools > Options dialog box appears, select Designer node
and uncheckPrevent saving changes that require the table to be re-created.”