Eriksoln, I'm glad to hear you are enjoying your Droid 3! I can certainly assist with your wallpaper being reset. Are you using a picture saved to the phone as your wallpaper or an application? Is this a live wallpaper? Are you charging with a wall charger or USB cable connected to your computer?
If you have installed an antivirus or task killer to your phone, uninstall those. I have seen some antivirus applications cause this issue. If your wallpaper is a live wallpaper, then a task killer may also close the application.
Please let me know so that I can further assist.
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