In SoundCheck 16.0 and earlier, there is the possibility that installing and running SoundCheck under different accounts will cause some dependent files to have incorrect permissions. That will cause Error 8 when trying to open SoundCheck or run sequences. To fix this, open terminal and run the following command on the SoundCheck folder:
sudo chmod -R 777
This will allow all accounts on the Mac to be able to read, write and execute all files within the SoundCheck folder.