I am also experiencing this issue on a Roku 3. Initially, I noticed it when my daughter tried to launch PBS Kids, and it needed to load it (my SD card slot has never recognized the microSD cards I give it). Instead of loading like normal, it just hangs at 0%. This went on for a good 10 minutes. I was unable to exit to home or anything else. I power cycled the device, and tried again, to no avail. I swapped the 16 GB SD card that was installed (but never recognized) for an old 1BG one I had laying around. It did recognize that card, formatted it, then attempted to load channels. It hung that way (again, unresponsive) for 6 hours (i went away and came back to see it still there). I've also attempted to check for updates, which also hangs, and then eventually causes the Roku to spuriously reboot.