I have tried to reformat on Ubuntu using gparted, in Windows using their tool, and OSX using Disk Utility. I have also attempted by using the terminal but also failed there. When I verify disk using Disk Utility, I get the following output: Verifying volume “REDSTRIPE” ** /dev/disk2s1 ** Phase 1 - Preparing FAT ** Phase 2 - Checking Directories ** Phase 3 - Checking for Orphan Clusters 168 files, 4507316 KiB free (1126829 clusters) MARK FILE SYSTEM CLEAN? no ***** FILE SYSTEM IS LEFT MARKED AS DIRTY ***** Error: This disk needs to be repaired. Click Repair Disk. But I am unable to repair disk. See OSX examples below: