At some point the "Plugins" menu was renamed to "Extensions" and with it the ID of the actual menu. It used to be IDS_EDITOR_PLUGINS, but is now IDS_EDITOR_PIPELINE.
Because of that c4d.gui.SearchPluginMenuResource() doesn't find it anymore without specifiying the identifier.
The default value (or even the function name) should probably be updated to reflect the change.
(Or for the time being maybe just give a warning in the documentation?)
Hi the fix of the default value is already on its way and will be included in the next release pack
Hi @Boony2000 with the latest update of Cinema 4D (R24 SP1), c4d.gui.SearchPluginMenuResource default value was fixed in Python.