Well if your writing ot you hd and you pull the USB cable out your corrupting the data and might subsequently make the hd unreadable. (someone here will probably elaborate the dangers of pulling out the cable without unmounting the hd first - as i'm not an expert). However if you haven't written anything on your hd and just use to access files then its alright (said carefully). I always recommend to 'unmount' Anyway have you tried to use disk utility to unmount the drive? You need to consider that the files system of the Mac is different to Windows. Windows uses FAT, FAT32, NTFS and so on. In order to read your drive must be FAT32 for both the Mac and the PC to read it. Mac cannot read NTFS
Drag the disc icon to your Mac’s trash bin; Right click on the disc icon and select eject; Press Command E; Next, try this method: Launch the terminal app and use the following command and then press enter: /usr/bin/drutil eject; If all else fails, you can try these methods: Boot your Mac into single-user Mode. At the prompt enter /usr/bin. There are several methods that you can try to eject a disc from a Mac: Press the Eject Button. Visual notes app mac. Press the Eject button on the keyboard. Click the Eject Icon. Click on the Eject symbol on the menu bar at the top, then select the name of the disc drive. Drag and Drop to Eject. Mint app mac os. Click and drag the disc drive icon from the desktop into the trash bin.