When you get “Runtime Error ‘380’ Invalid Property Value” when clicking Source Clipboard button in Legacy:
Please make sure that you have the most recent Legacy update by visiting https://legacyfamilytree.com/download-update. The update has a "patch" related to a Source error. Be sure to temporarily disable your internet security program(s) as some of these will cause serious problem for Legacy.
Do a check/repair of your family file. See the article "How to Check/Repair your family file - Legacy".
Next reset Legacy's default values. Please click on Options > Customize > Options for Default Settings > Reset to Legacy-Defaults and confirm the reset action.
With Legacy closed open your Documents folder and browse into Legacy Family Tree\Data and delete the files that end with .NC or .NC0, etc.
Try the Source Clipboard again. It should work.
If these steps do not fix the Source Clipboard problem, a clean re-installation will probably solve it. Please ask for the steps.