INTERNAL ERROR WITH LR Classic

[Digitizer]

Welcome to the forum, @judophotos

You might find the solution in this post:

V2.3 NLP will not open in lightroom!

Yes, @Digitizer is correct. Negative Lab Pro will not work currently from within that folder because of folder permission issues with Windows. You need to: Close Lightroom Move the plugin from C:\Program Files\Adobe\Common\Plugin-ins\NegativeLablPro.lrplugin to a folder you create on the root drive, for instance, C:\Plugins Re-open Lightroom. Go to File > Plugin Manager Click “remove” to remove the previous location of Negative Lab Pro, then click “add” and navigate to “C:\Plugins” to add the…