We have created a Saffire MixControl Uninstall App for your ease.
Please download, unzip and then run the enclosed App, found at the bottom of this page.
If you have an older Mac or would like to do this manually please remove the following:
Macintosh HD/Applications/Saffire MixControl.app
Macintosh HD/Library/Startup Items/Saffire/.*
Macintosh HD/Library/Application Support/Saffire/.*
Macintosh HD/Library/Audio/MIDI Drivers/SaffireMIDIDriver.plugin
Macintosh HD/Users/[yourusername]/Library/Application Support/Focusrite/.*
Macintosh HD/Library/Receipts/Install Saffire MixControl.pkg
A * indicates that you should remove the entire folder