Look for a folder corresponding to your version number (e.g., 13 or 14 ).

To help narrow down the search, could you tell me of Nitro Pro you are using (e.g., v13, v14, or Subscription)? If you purchased it through a corporate volume license , let me know so I can provide the IT admin retrieval steps. Share public link

While newer versions (v12 build 13 and later) encrypt the serial number for security, older versions may still store it locally. Inside Nitro Pro : Go to the About Nitro Pro . If you see a number like 504945XXXXXXXXXXXX , the full key is hidden and you must use Method 1 or 2. Windows Registry (v6 or older) : You can sometimes find it at: HKEY_LOCAL_MACHINE\SOFTWARE\Nitro\Pro\Version Spiceworks Community 4. Other Locations Activating Nitro PDF Pro

Look for emails from Nitro Software , 2Checkout , Cleverbridge , or ndraw .

Look for a registry string named or ActivationKey in the right-hand pane.

For physical deliveries from authorized resellers, look for a label inside the DVD case .