If Office Communcations Server or Lync is used in your company, you may encounter the following error when assigning a telephone number to a user: “A duplicate remote call control device URI already exists”
This means another user already has the telephone number assigned in its OCS properties. The easiest way to quickly find out who has the number configured, start a Powershell console with Active Directory snappin: Import-Module ActiveDirectory Get-ADUser -Filter ‘msRTCSIP-Line -like “*4154*”‘ -properties * | Select-Object name,msrtcsip-line In the above example, the cmdlet returns the user and its msrtcsip-line value that is causing the problem. The number 4154 is the telephone number in this case -> replace it with your own number 🙂
