Hi,
Some time ago I already posted this question: 
At the moment I've got Cadence Allegro version 16.6 P004 installed and I try to install the hotfix Hotfix_SPB16.60.072. Too bad I got the error: SPB 16.6 base release not found. ISR installation will be aborted. The switch release is aiming towards C:\Cadence\SPB_16.6 This is where i installed Allegro 16.6. Any idea why I get this error?
I've tried it with the license file of Allegro 17.2 and the license file of Allegro 16.6. Do I need to reinstall Allegro 16.6?
On my laptop I'm working with Allegro 16.3, 16.6 and 17.2. All the software versions are working and I use the Cadence Switch Release ofcourse to switch between the versions.
Hotfix SPB16.60.072 Base release not found