In my first try months ago with the 3TB drive (and without using mfsr), I didn't run any diagnostics on it. When it didn't perform up to par, I just integrated it into my system as another drive where it doesn't seem to have a problem. After reading through threads on this forum, I did run diagnostics on the 4 TB Red drive which were fine, and I also erased it entirely with lifeguard (which was pointless probably). I AM running on an antenna, not cable. Since the new season of shows is starting now, this was a bit of a last minute things (received the drive Friday). So to test it in the real world so I don't lose a bunch of shows to recording problems I did several sessions of recording 3 or 4 shows from the antenna at a time (at times even downloading from the Roamio using kmttg while also recording which I'm sure puts a much greater load on the drive) ... so far zero hiccups in the video that I've watched, so hopefully I'll be getting clean recordings! I'll check the RS corrected vs uncorrected ... I think I did that a long time ago, but will look into it again. Thanks!