If you simply want to have two different versions of FME Desktop installed on the same machine, it's simply a matter of installing them to different folders. Nothing more is needed, and you can have an unlimited number of versions installed in this way.

See also https://community.safe.com/s/article/installing-multiple-versions-of-fme

I understand the many versions and thanks for the response. The big question is the unattended installs - where a IT department only needs to add the installer to the the download center, then the end users are not required to enter credentials (normally by IT) to install the application. This is the purpose of the MS Download Center. We have attempted to perform this action however, the installer does not complete and also breaks the other installs. My assumptions is because you don't have alternate folders to install the application.

More information can be obtained at the following location for the download center:

Software Center.

Can this be done and has anyone been able to successfully perform this action with multiple versions of workbench?