Yeah, I didn't mean to imply that no one had 550 Pro's working with NPVR, it just seems like whenever someone has posted a thread saying they couldn't get their 550 Pro to work, no resolution could be found. I suspect there are different 'flavors' of the card, and/or different driver revisions that behave differently. In theory, there's no reason these cards shouldn't work, but for some they just don't.
server: NextPVR 5.0.7/Win10 2004/64-bit/AMD A6-7400k/hvr-2250 & hvr-1250/Winegard Flatwave antenna/Schedules Direct main client: NextPVR 5.0.7 Desktop Client; LG 50UH5500 WebOS 3.0 TV