Saving Table Times out in SQL Server 2005

I've run into this a few times, when you make a change to a table that is very big (eg million or more records) in SQL Server 2005 table designer, you typically get an message:

Saving Definition Changes to tables with large amounts of data could take a considerable amount of time. While changes are being saved, table data will not be accessible.

Usually followed by the error message:

Post-Save Notifications

- Unable to modify table.
Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.

I've seen this error when trying to make a column not null, or trying to modify an existing column.

To fix it, go to the Tools Menu and select Options then under Designers select Table and Database Designers the first option allows you to disable the timeout, or make it greater than the default 30 seconds.