I put together a small lab of computer work stations to edit short video and audio for the Broadcast Journalism and RTVF in a college. I chose to buy Glyph hard drives as they had a reputation of running quiet for open microphone use. I could hot swap the drives out to keep the edit bays functional, another neat feature. I called their technical support and had a wonderful conversation with a gentleman about how best to keep the dives up and running. I was told that the most important software to get was DiskWarrior by Alsoft. After a few years of using this product, I completely endorse its use. It does one thing, repairs disk directories. But it does it very well. I have never had a problem come out of running this utility. It solves problems; it does not create any. The down side is it takes a LONG time to load from a CD. I created a separate USB floater hard dive with an operating system on it and this software so I could cut down on the time it took to run the program. For my edit bays, I ran this program the beginning of each week. If for any reason I forgot or failed to run it past seven days, I found I began to see performance problems begin to increase in some of the edit bay computers. So for school lab use, run this once a week. For the home user, run it at least once a month.
In my opinion, of all the utilities I ran in my edit bays and home computers, directory problems come up being the most troublesome.
Tip: I found that it is best to run this program more than once. Keep running it (typically twice) until you do not see any more errors.