How to take the Enterprise Database “Offline” to do a cold backup.

When I try to take the working database offline using SQL server management studio I get one of these two (failed) results (see attached).  Am I right in that you should take the database offline to do a full synchronized backup before performing a major version upgrade?

The EPDM installation guide and the backup and restore best practices guide don’t go into detail about this.

Any help would be greatly appreciated.

Matt

Solidworks