You’ll lose everything on it, and you’ll have to re-partition it later. This will remove the 200 MB partition as well as all the other partitions on the disk, erasing the drive. You’ll now need to wipe the drive’s partition table entirely. On any version of Windows, you can press Windows Key + R, type diskmgmt.msc into the Run dialog, and press Enter. If you haven’t open the DIsk Management tool yet, you can do it by right-clicking in the bottom-right corner of the screen on Windows 8 or 8.1 and selecting Disk Management. For example, in the screenshot below, the external drive we want to wipe the partition from is “Disk 2.” It’s actually the third one in the list, but that’s because the first disk is “Disk 0” and the system counts from 0. Note the number of the disk you want to remove the partition from. You can’t actually use the Disk Management tool for most of this, but you can use it for one thing. RELATED: Understanding Hard Drive Partitioning with Disk Management If they’re in Time Machine backup format and you don’t have access to a Mac, you can restore Time Machine backups on Windows. If you have any important files on the drive, be sure you have copies of them before you continue. You can’t simply remove the 200 MB partition and leave any other partitions alone - you’ll be wiping the drive’s contents and starting afresh with a new partition table. This process will actually wipe the entire external drive. The 200 MB partition at the beginning of the drive will stubbornly refuse to be deleted, and you’ll have to go beyond the Disk Management tool to delete it. The one time when you’ll want to do this is when you were previously using a drive for Time Machine backups, but you’re done with that and want to use it for something else.

Healthy efi system partition windows 10