Service Pack 1 for SharePoint 2010 Products and its known issues

Service Pack 1 for SharePoint 2010 Products is Now Available for Download
Service Pack 1 includes stability, performance, and security enhancements that are a direct result of your feedback. 

IMPORTANT NOTE

It is strongly recommended to install the June 2011 Cumulative Update immediately after the installation of Service Pack 1. The June Cumulative Update includes several important security and bug fixes that are not included Service Pack 1. 

Installing Service Pack 1

Prior to installing Service Pack 1 you should carefully read the known issues and release notes at

http://support.microsoft.com/kb/2532126

Service Pack 1 includes all fixes released through April 2011 so it can be installed directly to RTM builds of SharePoint 2010 Products, or any prior Cumulative Update.
Install the service packs in the following order on every server in the farm.

1. Service Pack 1 for SharePoint Foundation 2010
2. Service Pack 1 for SharePoint Foundation 2010 Language Pack (if applicable)
3. Service Pack 1 for SharePoint Server 2010
4. Service Pack 1 for SharePoint Server 2010 Language Pack (if applicable)

The SharePoint 2010 Products Configuration Wizard or "psconfig –cmd upgrade –inplace b2b -wait” should be run once on every server in the farm following the final update installed.
The version of content databases will be 14.0.6029.1000 after successfully installation. For more in-depth guidance for the update process, we recommend reviewing the following articles. These articles provide a correct way to deploy updates and identify known issues (and resolutions).
Prepare to deploy a software update for SharePoint Foundation 2010
Install a software update for SharePoint Foundation 2010
Prepare to deploy a software update for SharePoint Server 2010
Install a software update for SharePoint Server 2010

Frequently Asked Questions

Q: Can I install Service Pack 1 on RTM builds of SharePoint 2010 Products?
A: Yes, Service Pack 1 can be installed directly on RTM builds; however, we suggest you install Service Pack 1 then apply the June 2011 Cumulative Update.
Q: Do I need to run psconfig after the install of every package?
A: No, apply all of the available packages then run psconfig - the database will only be updated once, to the newest version.
Q: Do I need to run psconfig on every machine in the farm?
A: Yes. Although database is already updated, the binaries on each server need to be set and permissioned using psconfig.
Q: Will there be a slipstream build including Service Pack 1 available for download?
A: At this time a slipstream build including Service Pack 1 is not available. 

Additional Resources

To learn about what’s new in Service Pack 1 read the Service Pack 1 for SharePoint Foundation 2010 and SharePoint Server 2010 whitepaper.
Learn more about installing updates for SharePoint 2010 at the Updates for SharePoint 2010 Products Resource Center
For a description of new functionality in Service Pack 1 see the Service Pack for SharePoint 2010 Coming Soon... blog post on the SharePoint Team Blog.