The information in this article applies to:
Receive following error during installation of Enterprise Manager with SQL Reporting Services:
Error installing reports : System.Web.Services.Protocols.SoapException: The report server cannot decrypt the symmetric key used to access sensitive or encrypted data in a report server database. You must either restore a backup key or delete all encrypted content and then restart the service.
The installation failure will cause an installation roll-back.
Once the rollback completes, take the following actions:
Or you can try to backup and restore the symmetric key. Please see the attached external link.