Dell VSM 4.6 ---> VSM 4.7 Upgrade not detecting ISO

Hi

Trying to update VSM 4.6 to latest version 4.7. Downloaded ISO update file(VSM-4.7.0-20170801.064620-256.iso)_ and attached to VM. Connected/Connect at power on are both ticked in settings for CD drive and attached to ISO image.

Logon to console and select Maintenance > Update appliance software version > Check for updates

Get the following:

Checking for available updates, this process can take a few minutes....
Available Updates -
No available updates found
press [enter] to continue...

Any ideas?