Immediately after entering the service account information for the installation of Symantec Mail Security for Microsoft Exchange, the error "Failed to verify user has mailbox" is displayed, accompanied by a pop-up message indicating "exemonadE2k10_E2k15.exe has encountered a problem and needs to close". The install does not complete successfully.
"Failed to verify user has mailbox" followed by "exemonadE2k10_E2k15.exe has encountered a problem and needs to close".
The Powershell 2.0 dlls are missing from the Global Assembly Cache. The registry entries for PowerShell 2.0 are present on the system, causing the SMSMSE pre-requisities check to pass successfully, but when the process responsible for running PowerShell commands during the installation attempts to execute, it cannot locate and load the PowerShell 2.0 dlls.
Install the PowerShell 2.0 engine via the Server manager: