One registration number works on one PC. If you have already registered Max Registry Cleaner on one PC and trying to register with the same registration number on another PC you will get this message.
If you are getting the message "Invalid Registration Number", while you are registering the product then this means that you are using the wrong registration number to register the software. Refer the email sent to you after you purchased the software which has the registration information and the name of the software you are registering.
If you have any questions please Contact Us and we will be happy to answer them!
We appreciate your time to offer us your feedback and encourage you to continue to let us know how we can improve our products. As our software is continually developed and improved, new features are always under consideration and your feedback is very helpful.