I have the Arris DCX3510-M PVR with a Western Digital external hard drive; both purchased from Shaw. Last night (and on at least one occasion before) the PVR deleted most of the programs that had been recorded on it. The deletions were random. Recent programs as well as old programs are gone. I was no where near maximum capacity of the PVR. I have called tech support, and they have no idea why this happens, when it will happen again, what I can or should do to prevent it from happening again, whether or not they can retrieve the deleted programs, whether or not I should replace my PVR, if I do replace my PVR, should it be with the same make and model or a new one, etc. There is no point in owning a PVR if it is randomly going to delete dozens of hours of programs that I recorded in order to watch later. That is kind of the entire purpose of a PVR. If Shaw cannot answer these questions for me, sooner than later, I will be forced to find a TV provider that stands behind its products.