Increasing the SSMS Table Designer Timeout Value

Q: I’m getting an error changing the schema for a table using the Table Designer in SQL Server Management Studio (SSMS). I’m trying to change a column from nulls allowed to not null. The table has about 200,000 rows.

When I go to save the change the Table Designer it gives me a warning that the change may take some time. I accept the warning, but then the operation fails with a timeout error. Is there some way to fix this problem?

 A: Yes. The Table Designer is hitting its default time out value and is ending the transation before it can complete. You can increase the time out value used by the SSMS Table Designer by going to the Tools menu and selecting Option. Next, expand the Designers node and then select Table and Database Designers. You should see a Transaction time-out after value. The default is 30 seconds. Increasing this value to something higher—perhaps 300 seconds—should fix your problem.