Open the Run: command Start Menu > Windows System > Run (or it is faster\easier to press the keyboard shortcut - Windows Key + R), or navigate to the C:\Users\<yourusername>\AppData\Roaming\CaptainSim

Type, or copy and paste %AppData%\CaptainSim\,  then press OK

Delete the p721 folder (p722 folder for the 727-200 Expansion Model, and p723 folder for the 727 Freighter Expansion Model).

Run the installer for the 727-100 Base Pack, 727-200 Expansion Model, 727 Freighter, and you should be asked to Activate them.

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