Finally, If I click the icon for SF Pro 11 on the taskbar, I get the 'Registration of Sound Forge Pro 11.0 requires el3evated privileges', I click next, the User Account Control appears, I click Yes and nothing happens. This time if I click Yes VP13 launches fine and I can right click an audio file on the timeline, select' Open Copy in Sound Forge' and it opens fine.

However, If I right click the VP13 icon on the taskbar, right click Vegas Pro 13.0 (64-bit)and choose 'Run as Administrator', the User Account Control comes up. When I click Next the User Account Control comes up but when I click Yes nothing happens. However, when I right click an audio even and choose 'Open Copy in Sound Forge' I get the message 'Registration of Sound Forge Pro 11.0 requires elevated privileges' etc. When I click on VP13 I do not get the User Account Control and VP13 launches fine. Then while editing I can right click on an audio file to 'open a copy in Audio Editor' and SF Pro 11 will launch fine for me. When I click on VP12 I get the User Account Control come up, 'Do you want to allow this app to make changes to your device', and when I click Yes VP12 launches fine. I have icons for Vegas Pro 12, Vegas Pro 13 and Sound Forge Pro 11 on the taskbar on my Windows 10 pc. I will try out some of the suggestions shortly. Hello again and thank you for your replies.

Sound forge pro 11 customer support