I stumbled across this while trying to find help for this exact same issue. It turns out to be extremely simple.
This works for Readyshare activated external USB harddrives(In my case).
Step 1. Login to your Netgear router.
Step 2. Go to the ReadyShare settings.
Step 3. Uncheck any "Workgroup" protocol you've selected to transfer across (Network connection/HTTP/HTTPS/FTP etc).
Step 4.APPLY the new settings.
Step 5. Click "Safely Rmeove USB Device"
While this may not help everyone and there may be a bigger issue here this is what worked for me.
Hope this helps you and anyone else who happens to stumble here trying to find help!
If you don't safely remove the USB device from your Netgear router you can expect to see weird permissions problems and or lost data once you plug the External Hd into a PC or laptop or direct access.
Make sure to ALWAYS safely remove USB devices that require you to do so!
