I have just started noticing that power surges or whatever it is that can cause the relationship between the dvr(s) and the external HDD expander(s) to go wrong so that the video gets corrupted. The shows are recorded apparently, as it is listed, but when you try to play it, it's not there with only a blank/black screen or only a small part of it or as more than likely with an error message about the external HDD not being connected. I have also figured out that it may be fixed by doing the unplugging the power to the dvr first and then the external HDD expander and then replugging first the external HDD and then the DVR - when powering off and repowering the dvr and external HDD to pause each action between 10-20 seconds that is between unplugging the power to the dvr and then the external HDD and replugging with the same pauses.
The question is what exactly is happening here and why does this seem to work? Is the relationship between the dvr and external HDD out of sync and what is it? I'm asking as a nontechnically minded person who have lost 3 dvrs to this problem with the many hundreds of recordings including the missed timer recordings and have being having the same problems with currently 2 dvrs , if they are related to this issue!
Power surges can damage drives and other electronics. Hard drives are mechanical devices and will eventually fail. Your best bet is to get a surge suppressor or battery backup for your DVR, tv, and associated electronics to help prolong it's life.
Also, you didn't mention which DVR you have. TiVo has places that you can have the dvr repaired or have the hard drives replaced. There are even option to do a self install of new drives into a tivo to increase their storage (more hours of video) or to just replace a bad drive.
The only DVR I'm familiar with is tivo, specifically the "tivo hd". I use a WD DVR expander on mine. The 1st one (500 gig) lasted 3 years. I'm on my 3rd year or so with another one (1TB). As stated drives die. when my first one died, it didn't take the DVR with it. I just had to replace the external drive.
Keep reading if interested or else ignore.
The tivo actually RAID's the internal and external drive in a RAID 0 fashion. If one of the drives is lost, all recorded movies are lost. Even if I tell the tivo to no longer use the external drive it will warn me that all recorded shows will be lost. The tivo has status functions that allow you to see which drive is failing.
If your DVR works in the same fashion, either your internal or external drive can be malfunctioning. Without any utilities to tell which drive is bad, there isn't much you can do. In fact, the most you can do is to disconnect the external drive and see if your movies work properly on just the internal drive. If it works ok, then your external drive is bad. If you still have problems, your internal drive definately has problems and there would be no way to tell the condition of the external until you got a new internal drive.
If the internal drive is bad, I'd expect your satellite/cable company to replace the dvr.