Serum interface doesn't display, I see a black box

This is probably due to Serum not finding or properly loading the "skin". You should try to update Serum by downloading the latest full version.

If you are on Windows, try moving "Serum Presets" folder from Documents\Xfer to C:\ so you have C:\Serum Presets\ and the folder is no longer in the \Documents\Xfer location.

Serum will ask for the new folder location next run.