How to solve error "save changes is not permitted" in sql server?

You can disable this warning in your sql server management studio by following these steps:

• Go to "Tools" in your management studio.
• Select "options" from tools menu
• from "options", select "designers"
• In "designers"-> from right hand side pane, uncheck "Prevent saving changes that require table re-creation"
• that's it you are done.

Here is the screenshot which may help

This error occurs as by default SQL Server Management Studio prevents the dropping of tables because when a table is dropped its data contents are lost as when altering a column's datatype in the table Design view and saving the changes, drops the table internally and then re-creates a new one.

According to https://docs.microsoft.com/en-us/sql/ssms/visual-db-tools/save-not-permitted-dialog-box?view=sql-server-2017

The Save (Not Permitted) dialog box warns you that saving changes is not permitted because the changes you have made require the listed tables to be dropped and re-created.

The following actions might require a table to be re-created:

• Adding a new column to the middle of the table

• Dropping a column

• Changing column nullability

• Changing the order of the columns

• Changing the data type of a column

If you want to remove the warning message open your SQl server Management studio(SSMS) and navigate to the menu Tools >> Options >> Designers and uncheck “Prevent Saving changes that require table re-creation”

That's it, you are done.