SOLVED: "Negative Lab Pro remains in Trial Mode even after entering my serial number"

Problem:

“I entered my Negative Lab Pro serial key into the Lightroom plugin-manager. It appeared to be successful, but then when I try to use Negative Lab Pro, it is still in trial mode, and I see my remaining uses counting down.”

Solution:

First, make sure you have the most recent version of Negative Lab Pro.

Then, follow these steps to force Lightroom to keep your Negative Lab Pro registration.

  1. Exit Lightroom
  2. Hold down Shift-Option (on Windows it’s Shift-Alt) as you double-click on your Lightroom app to re-open Lightroom. Keep holding them down and the dialog below will appear.
    reset-prefs
  3. Select "Reset Preferences"
  4. You will now need to add Negative Lab Pro back to the Plugin Manager, and reenter your serial number, but this time it should stick.