Preferences Plugins DirectX

Direct-X (DX) plug-ins settings
Enable DX plug-ins	By default, REAPER provides support for DX plug-ins. Clear this check box to disable support for DX plug-ins within REAPER.
Scan DX plug-ins on startup	Select this check box to force REAPER to scan for DX plug-ins each time REAPER is started.
Disable DX plug-ins scanning	Select this check box to stop REAPER scanning for DX plug-ins when the Add FX window is opened.
Scan for new DX plug-ins	Click this button to force REAPER to scan for new DX plug-ins.
Rescan all DX plug-ins	Click this button to force REAPER to rescan the entire DX plug-in list.