1. Are you using the right numbers and letters?  This may seem obvious, but worth checking closely.  Try and use copy+paste to minimize errors.

2. Have you installed the correct edition?  The Stop Motion Pro installation disc has a number of editions to choose from.  Make sure you have selected the correct edition to install - check your order details match the choice you are making when selecting the edition to install. 
This is not a problem if you download your copy of Stop Motion Pro. We send you the correct edition if you download via our website using your serial number.

3. If you register (make an unlock code) on one computer and then try to use the same numbers on another computer the software will not unlock.  The numbers are unique to each computer.  If you are installing the software on another machine you will need to create a new unlock code for the other computer.  Just use your serial number (sent when you ordered the software) and follow the instructions here on the new computer:

http://stopmotionpro.com/index.php/download-unlock/unlock-your-copy


4. If you are trying to unlock the same computer and the computer unlock code is not working then there may be another cause.  Have you been able to unlock Stop Motion Pro before on the computer before?  Have there been any hardware or software changes? (new hard disk drive or operating system etc).  This can make the unlock code invalid. 

Follow the online instructions above again from the start, and create a new unlock code.