You can probably tell from some of my more recent posts that I have been doing some work lately on SQL Server 2008. I have also recently (the last two months) upgraded my work desktop to Windows 7. As a result of this of this, and the continued migration away from SQL Server 2000 I have only installed the SQL Server 2008 client tools (Management Studio) onto my desktop and I use that for working on both SQL Server 2005 and SQL Server 2008 instances.

This week, for reasons beyond the scope of this post I wanted and needed to change the sa password on one of my SQL Server 2005 instances. No problem I thought, I already had SSMS 2008 open on my desktop. I connected to the SQL Server 2005 instance using Windows Authentication. (The SA account is not generally used) I opened the security folder, and then the logins folder, right-clicked on the sa login and selected properties. The properties box opened, I typed a new 'password' into the 'password and confirm password' dialogue box and clicked <OK>. To my shock and horror I got the following error:

Cannot set a credential for principal 'sa'. (Microsoft SQL Server, Error: 15535)

Well that surprised me, if it didn't surprise you. I tried to login using the old SA password and it logged in fine. I then realised that it must be related to changing the sa password of a SQL Server 2005 instance using SSMS 2008.

Well I cheated and remote connected to the server hosting the 2005 instance, and used the SSMS 2005 installed on there. I needed to change the password quickly but I wanted to figure out what had prevented me changing the password in SSMS 2008.

Returning to my test domain later in the day, I was able to recreate the problem again, simply by trying to change the sa password of a 2005 instance using SQL Server 2008 Management Studio. I went to search the web and found this:

http://support.microsoft.com/kb/956177

The solution is very simple, the "map to credentials" check box in the properties Window is not selected. The above article explains why this is the case. Tick the box and change the password and all is well.