Can you please post the script?

Also, as alternative, did you try to detach this DB in SQL 2008 R2 Express, copy to another place, attach back in SQL 2008 R2 (from original location) and attach in SQL 2012 from new location?

>Tried restoring to a non-existent DB with same error.
>
>I have always used the SSMS interface to restore and never had this issue.
>
>You can note my comments to Craig and Dragan. Something I am not quite following is going on.
>
>Bill
>
>>Did you try without creating a DB first?
>>
>>Also, instead of doing it through the interface, click Script on this interface and then run it from the script (you can post it here for inspection as well).
>>
>>>I am trying to move a SQLExpress2008R2 DB to SQLExpress2012.
>>>
>>>I a full backup of the SQL Express2008R2 DB. I then created a DB in SQLExpress2012 with the same name. Attempting to Restore the SQL2008 DB to the SQLExpress2012 DB generated the following security error. What am I missing here?
>>>
>>>
>>>TITLE: Microsoft SQL Server Management Studio
>>>------------------------------
>>>
>>>Restore of database 'Lepton' failed. (Microsoft.SqlServer.Management.RelationalEngineTasks)
>>>
>>>------------------------------
>>>ADDITIONAL INFORMATION:
>>>
>>>System.Data.SqlClient.SqlError: The operating system returned the error '5(Access is denied.)' while attempting 'RestoreContainer::ValidateTargetForCreation' on 'c:\Program Files\Microsoft SQL Server\MSSQL10_50.SQLEXPRESS2008R2\MSSQL\DATA\Lepton.mdf'. (Microsoft.SqlServer.SmoExtended)
>>>
>>>For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=11.0.3000.0+((SQL11_PCU_Main).121019-1325+)&LinkId=20476