After pairing two Lync 2013 Front End Pools and starting the backup service I found on one of the Front End Pools there was an LS Backup Service Error in the event log Event ID 4070 every 10 minutes. Event ID is below.
I checked a number of things file store permissions, SQL and used the get-csbackupservice –poolfqdn <PoolFQDN> |fl on both pools to check the backup service states on both pools.
One Pool was in normal state and the other was in error state. The pool with the import error was showing the user presence module error state whilst importing which confirmed what I found in the event log.
After discussing with James Brewster we decided the next best step was to find the XML file that was referenced in the error which was “63191593-1355-464a-827b-dc8555000f2f_0_2.xml.”
The Lync backup service using the Lync File Stores to replicate data across the paired pools so that was my first place to look. I searched the file stores and couldn’t find the XML file.
What I had noticed that their was a backup.zip file created on the opposite pools file store in the folder. <filestore1-BackupService-38BackupStoreUsersServicesPresenceFocusData which was creating and deleting itself very quickly.
I decided to try and copy the backup.zip and see what was inside. After opening the backup.zip I opened UserServicesPresenseFocus1-UserServices-9data. There I found the XML file. Whoop! Whoop! I was getting close 
I opened the XML file using Notepad ++ and went to the line number that was referenced in the Event ID line 1770449 and I found “urn:confs:MeetingholdersofR&S@sipdomainname.com”> I noticed the “&” in the sip uri which isnt right which made sense why it couldn’t be imported.
I checked Lync cscp and this user was enabled for Lync! I checked and this user was not required to have a Lync account so I deleted this user from Lync and checked the Event Log and ran the get-csbackupservice. Everything was normalstate and the LS Backup Service Error was gone !!!
Special thanks to James Brewster, fellow Risual UC consultant with his help with this one. Thanks Mate!
Thanks
Martin
Log Name: Lync Server
Source: LS Backup Service
Date: 25/07/2013 17:55:34
Event ID: 4070
Task Category: (4000)
Level: Error
Keywords: Classic
User: N/A
Computer: <Active Backup Server Front End Server Name>
Description:
Microsoft Lync Server 2013, Backup Service user store backup module failed to import a batch of documents.
Batch file: UserServicesPresenceFocus1-UserServices-9Data63191593-1355-464a-827b-dc8555000f2f_0_2.xml.
Exception: System.Xml.XmlException: ‘@’ is an unexpected token. The expected token is ‘;’. Line 1, position 170449.
at System.Xml.XmlTextReaderImpl.Throw(String res, String[] args)
at System.Xml.XmlTextReaderImpl.HandleEntityReference(Boolean isInAttributeValue, EntityExpandType expandType, Int32& charRefEndPos)
at System.Xml.XmlTextReaderImpl.ParseAttributeValueSlow(Int32 curPos, Char quoteChar, NodeData attr)
at System.Xml.XmlTextReaderImpl.ParseAttributes()
at System.Xml.XmlTextReaderImpl.ParseElement()
at System.Xml.XmlTextReaderImpl.ParseElementContent()
at System.Xml.Linq.XContainer.ReadContentFrom(XmlReader r)
at System.Xml.Linq.XContainer.ReadContentFrom(XmlReader r, LoadOptions o)
at System.Xml.Linq.XDocument.Load(XmlReader reader, LoadOptions options)
at System.Xml.Linq.XDocument.Parse(String text, LoadOptions options)
at Microsoft.Rtc.BackupService.BackupModules.XdsBackupModuleBase.GetNumberOfDocsInBatchFromXml(String batchXml)
at Microsoft.Rtc.BackupService.BackupModules.XdsBackupModuleBase.ImportTask(List`1 batchesToImport, Int32 startIndex, Int32 endIndex).
Cause: Application error. Please look through the exception details for more information.
Resolution:
The user store backup module encountered an import failure. If the problem persists contact product support.
