Sonicfire Pro serial numbers are formatted as a single letter followed by eight numbers.
If you requested a free Sonicfire Pro 5 Express Track serial number, your number may begin with the letter O (as opposed to the number zero). Make sure you are typing the serial number in properly. If you are copying and pasting the serial number, be sure that there are no leading or trailing spaces that were also copied, as that will cause a mismatch. Try manually typing in the serial number as one letter followed by eight numbers and if the serial number is valid, the Ok button should enable and will allow you to proceed
If you recieved a serial number with a bundle such as Toast Titanium 10 or Avid Media Composer 4, you may need to update Sonicfire Pro to version 5.5 or above for the serial number to be recognized. Please download and run the patch update from this page. Once updated, launch Sonicfire Pro and it should accept your assigned serial number.