Today I helped a customer who had received a warning from DrivePulse reporting corruption on his Macintosh HD volume and that it needed to be repaired. When he opened Drive Genius 3 he was not able to run Repair because it was grayed out so he contacted support for help. I explained to him that in order for Repair to run, the volume needs to be unmounted but since he wanted to Repair his primary startup drive (Macintosh HD), he would need to startup from another volume and he should have a current backup of his data. I told him that he could use either a secondary startup drive, a bootable clone, or the Drive Genius 3 DVD (Older Macs only) as his startup disk and then run the repair from there. He did have an external hard drive with Mac OS X Mountain Lion installed on it so he was able to start from this drive and then use Drive Genius to run the Repair on his Macintosh HD. The Repair completed successfully and he was able to start using his computer again without any issues.