When a GPX or FIT file with ´Read Only’ attribut is copied to the Newfiles directory, the Edge 1040/1030/1030 plus enters in an infinite loop on poweron, when the loader reads the GPX files written in Newfiles directory to convert them in FIT then try to remove the GPX source file.
Workaround (waiting Garmin bug correction) is to poweroff the device, then boot in USB Mass Storage : hold down LAP button while powering the device by plugging the GPS to a PC with the USB cable, wait until the GPS enters in Mass Storage ( wait up to 40s)