got my arc 10 days ago, loaded a few movies, some epubs, photos, and mp3s.
It took a while to figure out how to use the supplied apps but all seemed to be working and I was begining to like the ARC. Then I started having problems side loading, ARC would appear in my win7 explorer window and files would start to copy, and then the arc would dissappear from the explorer window! A shut down and restart would get it back and then files would copy but sometimes it would take 2-3 restarts for it to keep working. OK I can live with this for a while, then yesterday NO SOUND! I played with the volume switch and the settings menu to no avail. In the settings menu for notifications if I changed to different sounds then I could hear that sound but no sound from any app. Called KOBO support today and after several suggestions we did a factory reset. Had to start right from the beginng and go thru the update and the rest of the start up crap. Still only notification sounds and no sounds from the mp3 player or screen touches. Apparenly their is no Tier two help available on the weekend so the rep I had could not help me any further.
I have not loaded any apps and only side loaded a few mp3s to use to see if I had any sound so it is not a app conflict unless it is one of the preloaded apps. Also had the ARC dissappear from my coputer screen while downloading the mp3s. tried a new usb cable to make sure that it was not the cable.
Getting very frustrated, regretting buying the ARC.