Solution 1: Restart your Mac computer No matter what happens to your Mac computer and makes your Macintosh HD unmounted, the first and foremost solution is to shut down your Mac computer and restart it up again. After recovering data from the Mac hard drive that is not mounted in Disk Utility, you can follow the solutions to fix the issue.Founded in 1961, Sigma Corporation prides itself on high quality and innovative photographic equipment. Sigma Corporation of America is a subsidiary of the Sigma Corporation, a Japanese based family owned manufacturer of DSLR cameras, camera lenses and camera accessories.
