I purchased Elements 11 at Costco.
Can I intall it on my 3 computers??
Your license only allows it to be activated on two computers at once.
However you can use the trial version on any number of computers, but just for 30 days.
Are you talking about 3 different computers ? Or In one computer with 3 user -one admin and other 2 with standard?
In first case you should have to go one trial version and for 2nd case there is no problem only one installtion solve your problem