Microsoft has released released Update Rollup 4 for Exchange Server 2010 SP1 to the Download Center. Microsoft has addressed some issues reported by customer by this, please do the testing before you plan for an implementation.
MS had to re-call and release the update due to below scenario,
While fixing a bug that prevented deleted public folders from being recovered, we exposed an untested set of conditions with the Outlook client. When moving or copying a folder, Outlook passes a flag on a remote procedure call that instructs the Information Store to open deleted items which haven’t been purged. Our fix inadvertently caused the RPC to skip all content that wasn’t marked for deletion because we were not expecting this flag on the call from Outlook on the copy and move operations.
Please read more here - Exchange Team Blog
Now MS has re-released the update and is available to download @ Microsoft Download center. Please download it here Update Rollup 4 for Exchange Server 2010 SP1. Please also read the release notes from MS Exchange Team Blog before you plan to install the update
Some of the addressed issues are,
But, MS is still working with Arabic and Hebrew language installer to incorporate these fixes, hence MS advises for the customers who are using iether of these language version to download the engish version of the rollup.
Note - Please disable your forefront before the installation and enable it back after you complete the installation(fscutility /disable and fscutility /enable). If you fail to do this, your IS and transport service will not start after the update.
Read MS Blog Release notes for more information.