I have a Western Digital 1TB Hard Drive (External). I use it 99.9% of the time on my Windows 7 64bit computer to store pictures/videos and backup important files. It was working fine until I plugged it a MAC to backup files from that computer. It was a simple copy and paste from the MAC to the External HDD. After copying the files from the MAC, I plugged it back into my PC. My PC no longer recognizes my external HDD. I unplugged the power, plugged it back in. Same with the USB cable. Rebooted. Then my computer wouldn't reboot and windows did its automatic self repair. Nothing. I unplugged EVERYTHING and left it that way for about 30 minutes. I plugged EVERYTHING back to my computer and turned it on. Windows booted up fine. I plugged in the external HDD and windows had that little icon telling me it was installing drivers. I was excited to think that it finally would recognize my external HDD. Of course, it didn't work. I took the hard drive out of the casing/box. I know this voids the warranty... but the warranty has already expired on this junk. I plugged it directly to my desktop's eSATA. It shows up in Device Manager fine. In Computer Management's Disk Management, it tells me I have to initialize the disk before I can access it. BUT WHY WHEN IT WAS WORKING FINE BEFORE!?!? if Mac uses different formats, then the Mac shouldn't have been able to see all my files before I did the copying. The Mac was able to write on the disk fine when I created directories. And the Mac successfuly copied the files onto the Hard Drive. I don't see how something that uses different formats can do all that. My girlfriend (who owns that awesome MAC computer) said she googled my problem and read something that MAC erases ****** when you plug anything into a MAC. I heard of similar problems with mp3 players that have music already on it. What kind of crap is that? Now I would just like to figure out why it became corrupted by a simple copying of files from a ********ing mac. Because if MAC erased my hard drive, why the hell did it even bother letting her copy my files onto it to begin with? Thank you in advance.