I am copying this from a nice post from Ed Lehman, MSFT. Service pack 2 for SQL Server 2005 has an update. Here is Ed’s text:An issue was recently discovered with SQL Server 2005 SP2 which might impact customers using cleanup tasks in Maintenance Plans and SQL Server Integration Services packages. The issue is described in detail at  http://support.microsoft.com/kb/933508. We have created a General Distribution Release (GDR) #50000939 to address this issue which is available for download and we have included the GDR in a refresh of the SP2
installation package.

Customers who download SP2 starting Monday, March 5th, 2007 will not need to need any further action since the refreshed SP2 installation package includes the necessary GDR.

We recommend that everyone who has downloaded and installed SP2 prior to March 5th, 2007 apply the GDR either from Microsoft Update or by downloading it directly from http://go.microsoft.com/fwlink/?LinkId=85124. As described in the KB article (http://support.microsoft.com/kb/933508), this is primarily for customers who use cleanup tasks in maintenance plans and SQL Server Integration Services packages.

Maintenance Plan Changes in SQL Server 2005 SP2

Users of SQL Server 2005 maintenance plans and SQL Server Integration Services should be aware of a change in SP2 that affects existing cleanup tasks until updated using SQL Server SP2 tools.

Who is affected?
You are affected if you use cleanup tasks in Maintenance Plans and SQL Server Integration Services packages, those plans include a History Cleanup Task or a Maintenance Cleanup Task, and you install SQL Server 2005 SP2. Users of SQL Server 2000 legacy maintenance plans are not affected.

What is the issue?
When SQL Server 2005 was released, cleanup intervals were measured in days, weeks, months, or years. In response to customer feedback, SQL Server 2005 SP2 includes significant enhancements to maintenance plans. These include an enhancement that lets users specify the cleanup interval in hours. The change in intervals caused the initial release of SQL Server 2005 SP2 to misinterpret existing cleanup task intervals in maintenance plans and Integration Services packages. This can lead to the files being cleaned up earlier than intended. The issue is described in detail at http://support.microsoft.com/kb/933508.

What if I have already installed SP2 on my server?
If you downloaded SQL Server 2005 SP2 before Monday, March 5th, 2007, install a general distribution release (GDR) update for those SQL Server 2005 SP2 installations. The GDR is available from the Microsoft Download Center at http://go.microsoft.com/fwlink/?LinkId=85124
After you install this GDR, you might have to restart your computer.

This GDR is also available through Microsoft Update, and will be applied automatically if you are using automatic updates. However, if you are using failover clustering, you must download and apply the GDR manually. Microsoft Update will not apply the GDR to failover cluster nodes.

What if I haven’t yet installed SP2 on my server?
SQL Server 2005 RTM and SQL Server 2005 SP1 do not have this issue, and the current SQL Server 2005 SP2 download is updated to resolve this issue. If you have not installed the initial release of SP2, you can download the current release and install it.

Note: If you try to apply the SP2 refresh over a previous SP2 installation, no files are updated. Instead, use the general distribution release (GDR) update below.