• Before starting the update, make sure your phone has enough battery power. If the phone battery level is too low, your phone will prompt you to charge the battery before starting the update. 
  • Your phone is backed up automatically when you update your phone software. Should there be any problems later, you can restore your phone to its previous state.
  • Check that your phone is set to the correct date and time. With a wrong date or time, your phone might not be able to access the updates.
  • Make enough space on your phone for the update. If necessary, remove a few unwanted apps or other large items. To see how much free space you have on your phone, on the start screen, swipe left to the apps menu, tap Settings > About, and check the amount of available space.
  • Free up space on your computer, as you need enough space to download the software update, and to save a backup of your existing phone software, settings, and media files.
  • If you can't find a solution to your problem in the info above, you can also try our Discussions community, or the Microsoft support pages.

If there is a problem, try the Installing or updating your Windows Phone 7 software wizard. It provides step-by-step instructions to resolve the most common problems. If you get an error code, write it down. To find out what went wrong and what you can do about it, check this page.