I recently had the pleasure of experiencing the dreaded “access denied” error when trying to share a USB drive with a Windows 7 machine. Here’s how to fix it.
I have a USB disk (Fantom 1.5 TB “green” drive) that I share with multiple operating systems: OS X, Linux, and multiple versions of Windows. I had not tried to access it using Windows 7 before, and when I did, I thought things were okay initially: Windows gave the typical “installing drivers … ready for use” messages when I connected the drive. But from there things got a bit strange: Windows gave the drive’s NTFS partition a drive letter and knew how much space on it was used and free, but when I tried to access the drive’s data via an application or Windows Explorer, I got the error: “[My disk label] is not accessible. Access denied.” I started poking around with ownership and permissions, but this resulted in odd “you are not the owner” errors, or even worse: messages that claimed that Windows could not determine the owner of the device.
I did a lot of searching for an answer, and found suggestions to make additional changes to permissions and ownership, but none of these worked. Finally, there was something that did work: apparently, Windows 7 simply can’t make sense of the partition table on drives that were partitioned by earlier Windows version. I didn’t want to hose my entire drive, or to mess up the disk’s partition table so that my other machines wouldn’t be able to access its existing data.
The solution was to download a free partitioning product called Partition Wizard Home Edition, and to have this application simply scan — not edit anything, but just scan — the existing partition table on the drive. For whatever reason, after this scanning, which took less than a minute on my drive, Windows 7 was instantly able to view the contents of the disk and allowed me to access its contents.