I have a Swann DVR8 with Pro 510 cameras. They are driving me crazy as all cameras start recording when they switch from daylight to IR. On a cloudy day I can get 100 emails notifying me that they are recording. I've tried reducing sensitivity and I only have a very minor area for each camera to detect motion. All cameras are inside the home and none are facing windows.
Swann's answer "Buy more expensive cameras". Terrific, they didn't suggest this when I purchased the system.