Disk-Arbitrator - A Mac OS X forensic utility which manages file system mounting in support of forensic procedures
Disk Arbitrator is a Mac OS X forensic utility designed to help the user ensure correct forensic procedures are followed during imaging of a disk device. Disk Arbitrator is essentially a user interface to the Disk Arbitration framework, which enables a program to participate in the management of block storage devices, including the automatic mounting of file systems. When enabled, Disk Arbitrator will block the mounting of file systems to avoid mounting as read-write and violating the integrity of the evidence. You can find links to compiled executables on the releases page.