DoubleTake's registration window looks like this:
Check list to why the serial number may not work
Both the "Registered to:" and the "Serial number" must be filled out with the name and information from your registration email.
If you name has letters like ü or ø in it the accents are stripped off to make it compatible with different email applications.
Upper and lower case letters matter in the "Registered to:", and you must enter them as in the registration email.
The serial number only use uppercase letters.
Some letters an numbers may look alike: 0 and O, I and 1 and S and 5. Copy and Paste will avoid this problem.
If you have not gotten the registartion email, it could be because it has been caught by your spam filter, or if your internet provider has set up a spam filter
You can contact me by email. I will reply as fast as possible (I live in Denmark - Central European Time).
Phone: +45 47383921