You have a table in Microsoft SQL Server 2008 R2 that has no sparse columns.
You run an ALTER statement to delete one column from the table.
You run another ALTER statement to add one sparse column to the table.
In this scenario, an access violation may occur after you perform some operations on this table.
Cumulative update information
Cumulative Update 5 for SQL Server 2008 R2 Service Pack 2 (SP2)
The fix for this issue was first released in Cumulative Update 5. For more information about how to obtain this cumulative update package for SQL Server 2008 R2 S2008 R2 SP2, click the following article number to view the article in the Microsoft Knowledge Base:
2797460 Cumulative update package 5 for SQL Server 2008 R2 S2008 R2 SP2
Note Because the builds are cumulative, each new fix release contains all the hotfixes and all the security fixes that were included with the previous SQL Server 2008 R2 S2008 R2 SP2 fix release. We recommend that you consider applying the most recent fix release that contains this hotfix. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
2730301 The SQL Server 2008 R2 builds that were released after SQL Server 2008 R2 Service Pack 2 was released
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.