Update (November 16th): It turns out there’s a serious bug affecting DAGs after installing RU5. Recommendation is not to deploy RU5 while Microsoft investigates the issue. Meanwhile, the RU was also pulled. Note that this is the exact reason why I emphasize on not rushing updates in production and run them in test and acceptance environments first. When testing is not an option (but there are lots of options there with free virtualization technologies available), I recommend maintaining an incubation period of at least 1 month and monitoring sites like TechNet forum or related comments on the EHLO blog for issues.

Today the Exchange Team released Rollup 5 for Exchange Server 2010 Service Pack 2 (KB2719800). This update raises Exchange 2010 version number to 14.2.328.5.

Here’s the list of changes in this Rollup:

• 2707146 IRM-protected messages cannot be returned in search results if the messages are recorded and sent to an external contact in an Exchange Server 2010 environment
• 2710975 Some MAPI property objects in an ANSI .pst file contain unreadable characters if you import the file by using the “New-MailboxImportRequest” cmdlet
• 2712001 ExTRA.exe does not collect data if you select a scheduled task for a data collection in an Exchange Server 2010 environment
• 2712595 Microsoft Exchange RPC Client Access service crashes when you run the New-MailboxExportRequest cmdlet in an Exchange Server 2010 environment
• 2716145 Store.exe crashes on an Exchange Server 2010 mailbox server if a VSAPI based antivirus software is used
• 2717522 Microsoft Exchange System Attendant service crashes on an Exchange Server 2010 server when you update the OAB that contains a DBCS address list
• 2720017 An RBAC role assignee can unexpectedly change a DAG that is outside the management role group scope in an Exchange Server 2010 environment
• 2727802 Microsoft Exchange Replication service crashes intermittently when you try to move mailboxes from an Exchange Server 2003 server to an Exchange Server 2010 server
• 2733415 Event ID 1 is logged on the Exchange Server 2010 Client Access server in a mixed Exchange Server 2010 and Exchange Server 2003 environment
• 2733609 Email message and NDR message are not delivered if an email message contains unsupported character sets in an Exchange Server 2010 environment
• 2743761 DAG loses quorum if a router or switch issue occurs in an Exchange Server 2010 environment
• 2748766 Retention policy information does not show “expiration suspended” in Outlook Web App when the mailbox is set to retention hold in an Exchange Server 2010 environment
• 2748767 You receive an NDR message that incorrectly contains recipients of successful message delivery in an Exchange Server 2010 environment
• 2748870 Declined meeting request is added back to your calendar after a delegate opens the request by using Outlook 2010
• 2748879 You cannot access a mailbox by using an EWS application in an Exchange Server 2010 environment
• 2749075 A copy of an archived item remains in the Recoverable Items folder of a primary mailbox in an Exchange Server 2010 environment
• 2749593 Outlook logging file lists all the accepted and internal relay domains in the Exchange Server 2010 organization when you enable troubleshooting logging
• 2750293 Items remain in the “Recoverable Items\Deletions” folder after the retention age limit is reached in an Exchange Server 2010 environment
• 2750847 An Exchange Server 2010 user unexpectedly uses a public folder server that is located far away or on a slow network
• 2763886 “The operation failed” error in the Outlook client when you open a saved message from the Drafts folder and then try to send it in an Exchange Server 2010 environment

As of Rollup 4, its no longer required to disable/re-enable ForeFront Protection for Exchange using the fscutility to be able to install the Rollup properly. However, if you want to remain in control, you can disable ForeFront before installing the Rollup using fscutility /disable and re-enable it afterwards using fscutility /enable.

If you want to speed up the update process for systems without internet access, you can follow the procedure described here to disable publisher’s certificate revocation checking.

If you got a DAG and want to properly update the DAG members, check the instructions here.

Note that Rollups are cumulative, i.e. they contain fixes released in earlier Rollups for the same product level (RTM, SPx). This means you don’t need to install previous Rollups during a fresh installation but can start with the latest Rollup.

As with any Hotfix, Rollup or Service Pack, I’d recommend to thoroughly test this rollup in a test and acceptance environment first, prior to implementing it in production.

You can download Exchange 2010 SP2 Rollup 5 here.