Why does my Mac somehow "corrupt" every external hard drive it touches, such that they don't work with PCs any more but they continue to work with the Mac? Details: I have two USB external hard discs. When I started, they both worked fine with my PC. Then I plugged one into my MacBook Pro - the Mac saw everything on the drive and was able to copy it. Then I dragged the drive's icon to the eject icon. The drive's icon dissappeared, and I waited a while. There was no "safe to remove hardware" message like a PC would have, so I just unplugged it. Upon plugging it back into the PC, it didn't work. The "safely remove hardware" icon in the system tray of the PC did appear, and the USB window in my control panel says "Unknown device". Upon unplugging the drive from my PC and plugging it back into the Mac, it did work. The Mac can see the drive, not the PC. I did this with another drive, and the same exact thing happened. Now neither drive works with the PC, both still work with the Mac. I didn't reformat either of the drives, they both contain data from before I owned a Mac and the Mac can access that data. What happened? Thanks.