Best thing to do is download a "default" file with little or no devices in it. This will "clean" out the remote and allow you to download your file. As for size, I have several Whole House control systems with at least 300 to 400 pages of custom graphics and animations involved. The size doesn't matter here but what does is that the file you used was either a CCP original file or a MX-980 stand alone file. If you converted a stand alone into CCP it is very possible that the file became corrupt.