Serial number does not exist

[Larry Stout]

I'm having similar problem. I've been running on Pro 12 and purchased upgrade to Pro 13 yesterday. I deactivated 12 but when I entered the serial number for pro 13, I get an error message telling me that number doesn't exist.

[Allain Umailin]

Hello @larrystout,

Thank you for reaching out to us through our Community Forums!

Please be informed that 'The serial number entered does not exist' means the serial number you are trying to activate is for a different version of Nitro Pro. Looks like we need to uninstall the current version of Nitro Pro on your computer and install Nitro Pro 13. We then activate it using your serial number. Kindly follow these steps:
 
1. Uninstall Nitro Pro from your computer by going to Control Panel > Programs > Programs and Features then reboot the machine.

2. Please clear all your downloads folder or delete all downloaded Nitro installers. This step is important because we noticed that if you are saving all the installers and you download them in the same folder (like the downloads folder), the EXE can pick up any MSI installer in that folder and you may pick-up one of the older builds instead of the newly downloaded package.

3. Download your Nitro Pro 13 using these offline link/s:

x32 http://install.nitropdf.com/professional_13353685/en/retail/nitro_pro13_ba_x86.msi
x64 http://install.nitropdf.com/professional_13353685/en/retail/nitro_pro13_ba_x64.msi 

To know if you have 32-bit or 64-bit, please refer to this article:
https://support.microsoft.com/en-ph/help/15056/windows-32-64-bit-faq 

4. After installation, you can activate by opening Nitro Pro, clicking on the Help tab > About Nitro Pro > Activation and entering your new serial number.

Thank you for choosing Nitro and I hope this helps.