If anyone finds those .gpk or .mrk files annoying you can create a CMD script to quickly and easily delete them.
Open notepad.
paste:
del “E:\FOLDER NAME*gpk” /s/f/q
del “E:\FOLDER*mrk” /s/f/q
pause
Change E: to the drive where your folder exists.
Delete either line of code if you don’t want that extension deleted.
File Save As whateverfilenameyouwant.cmd
(must have the .cmd extension added)
Close Wavelab.
Right-click the CMD file and run as administrator.