what operating system? sounds like you're using the 09hr as the card reader. what if you take the SD card out and put it in an actual card reader? try a different usb port if you continue to use the 09hr as the card reader. I have a mp3 player that wouldn't mount on my system but would charge and show it connected to resolve it, I had to disconnect a USB webcam. You have rebooted right?
I would Never, ever drag and drop files from a recorder... That is a very risky workflow. I once had to do a recovery for a mac user who lost data that way.
You should copy the files. If they are copied correctly, only then do you delete them from the recorder.
How you define "copied correctly" is a personal decision. I use rsync, which does extensive checksums (a single md5 on a large file is not sufficient). Though these days I typically produce a final 16 bit version before deleting from my source media.
are the files copy protected on the recorder? I think that would only affect them from being deleted but it may be worth checking that.