Reset a plugin installation

The plugin-specific preferences accessed via LrPrefs are stored in LR's preferences.  LR itself also stores some information about plugins in its preferences.  So to clear all information about a plugin from LR, you can reset preferences:

https://www.lightroomqueen.com/articles-page/how-do-i-reset-lightrooms-preferences/ 

That article explains how to save the old preferences and restore them if resetting doesn't help.

If you want to clear just that plugin's preferences set via LrPrefs, you could use the function below. But note that there may be generic information (e.g. window positions) that LR has stored in its preferences that wouldn't be cleared by this function.

--[[----------------------------------------------------------------------------
public void
deletePrefs ([string pluginId])

Deletes all key/values for the given "pluginId" (defaults to the 
current plugin).
------------------------------------------------------------------------------]]

function Util.deletePrefs (pluginId)
    local prefs = LrPrefs.prefsForPlugin (pluginId)
    for k, _ in prefs:pairs () do 
        prefs [k] = nil 
        end
    end