Hi ncm,
Try unplugging all devices and then resetting the MAX configuration database (Tools>>Reset configuration data). Just FYI, this will delete all tasks, global virtual channels, scales, and devices in MAX, though the latter will repopulate when you restart your computrer and plug your devices back in.
If this doesn't help, then try force reinstalling NI System Configuration.
This is the link to the most recent version: http://www.ni.com/download/ni-system-configuration-14.0.1/5014/en/
This is how to force reinstall software: http://digital.ni.com/public.nsf/allkb/ADD22E807D5A12AD862579EC00760F79
Regards,
David R
Systems Engineer
National Instruments