This applies to the Current Saffire Range

Occasionally the permissions for Saffire MixControl will be damaged following the restoration of a backup from Time Machine or Migration Assistant.

This is usually resolved by moving the following file to the trash:

Mac HD > Library > Preferences > Saffire.startup

If you continue to experience problems with Saffire MixControl crashing upon opening you should get in contact with the support team to further troubleshoot your issue.