>>> First, use the Uninstaller file from the UC 1.7.4 pkg. This will clean out most.
>>> Then click your Go menu and select Go To Folder.
>>> type or copy/paste this precisely.
/System/Library/Extensions
>>> Click GO
>>> Find the PaeFireStudio.kext file and trash it.
>>> Then close the windows currently open.
>>> Click the Go menu again and select Go To Folder.
>>> Type or copy/paste this precisely.
/private/var/db/receipts
>>> Find and trash these files.
com.presonus.pkg.universalcontrol.bom
com.presonus.pkg.universalcontrol.plist
>>> Empty Trash and restart
>>> Then run the UC 1.7.4 installer.
>>> Connect the FireStudio to your computer and power in ON.
>>> Click the Settings menu on the small Universal Control window.
>>> Check Firmware and Factory Reset.