I have searched and read til I am blue in the the face??? I have a 536 in the house, one in the car and a 436 portable. Have had for several years and never had much problems with sd cards. All of the sudden I have 7 fl's out of 28 or so that are not working. In other words it will say nothing to scan if you shut the workings off. Tried reprogramming a couple of the fl's and it didn't work. Yes, did use the check list etc. I will admit I hardly shut off scanner in vehicle. Have I got some bad cards? I am thinking I need to get some MLC-16+ cards according to Upman. If I do, can you just put them in and write to scanner and you are good to go? The reason I found this is that my 996xt never misses a beat, have one in house and one in another vehicle.