If you are having to utilize the Paragon driver/extension, it sounds like the drive is NTFS formatted. Are you going back and forth between PC and Mac computers? I've had issues with my external drive on the Mac before, and plugging in on my work PC did the trick.
In general I have found the Paragon driver to be quite frustrating. First it annoyed me to have to pay for the functionality. After doing so, it seems to have stopped working as I've upgraded to various OS and currently on El Capitan.
In my case, I have a Seagate external drive and they offer a free "bastard" Paragon driver that only works on Seagate drives. Let me rephrase, it's SUPPOSED to work on them. It has never done so for me, which is why I bought the commercial version a few years back.
Recently, this become a thorn in my side once again as I was trying to do some backups. If you aren't aware, you can use the command line to force OS X to read & write NTFS drives without the use of the Paragon driver.
http://osxdaily.com/2013/10/02/enable-ntfs-write-support-mac-os-x/
The downside (at least for me) is that it no longer automounts on the desktop like before. You can get around this by creating manual shortcuts and/or utilizing /volumes so it pops in the Finder view.
So far this seems to be the less of two evils for me. Maybe it can help you too.