Windows Enterprise Desktop

Oct 29 2012   4:33PM GMT

Interesting Contortion to Reclaim Time Machine Disk for Windows Re-Use

Posted by: Ed Tittel

I’m sending off my 2010 MacBook Air to Virginia, so my high-school age niece can use it regularly for schoolwork (I never really found as much call for it was I thought I would, once I finished tech editing Chris Minnick’s WebKit For Dummies late last year). That left me with a USB drive that I’d been using for Time Machine backups that I wanted to repurpose for backing up my Lenovo Windows 7 and 8 notebook PCs (an X220 Tablet running Windows 8 Pro, and a T520 notebook running Windows 7 Professional). But when I tried to reformat the drive to make the switch to Windows, I learned two interesting things:

1. Mac OS X lays down a 200 MB EFI partition at the head of its disks, even USB-attached drives.
2. The built-in Windows Disk Management tool diskmgmt.msc won’t delete or format over EFI partitions.

Obviously, I needed a different tool for this job, and I found it in Paragon Software’s Hard Disk Manager 12 Suite. Using this toolset, I was immediately able to grab and delete the offending EFI partition, after which I reformatted the entire drive (nominal 750 GB, 698 GB reported in Windows Explorer) without any further difficulty. I’ve already backed up both Lenovo machines, and sucked up nearly 80 GB of space on this drive, a Samsung SpinPoint HD753LJ hard disk.

This little adventure reminded me that where there’s a will there’s a way to get things done in Windows, but also that exercising such will must sometimes involve tools outside what Microsoft uses to stock its basic OS toolbox. For dealing with disk issues of all kinds — including¬† OS migration, partition management and resizing, and repair — I’ve found the Paragon Software tools to be straightforward to use, entirely reliable, and reasonably affordable. Be sure to check them out at the Paragon Software site online; free trials (some with functionality limited to virtual mode operation only) are available for most of its products. Good stuff!

Concluding Note:
I realized that I was guilty of GUI thinking in jumping out of the Windows corral to tackle this problem, so these contortions are at least partly of my own making. Of course, I could have turned to the command line instead, where the diskpart utility could have done away with the offending EFI partition pretty quickly (along with the rest of that drive’s existing disk structure). All I had to do was use the diskpart command, then issue the following sequence of instructions:

DISKPART> list disk
DISKPART> select disk y

In this command sequence,¬†y stands for the drive number for the target drive, so the target drive need not even be mounted as a Windows file system volume to perform this task (a good thing, since any Mac OS drive won’t mount by default in Windows). The concluding exit command is required to exit the diskpart utility, after which you can close the command window.

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