Windows 10 prototypeMicrosoft has finally made Windows 10 Mobile Build 10136 live for those Windows Insider who opted to roll-back to Windows Phone 8.1 to get this update. But before you upgrade that you will certainly do if you have rolled back already to Windows Phone 8.1 then here are some known issues. But a super-important must read info first.

For those of you that do choose to make the jump to this build it is SUPER IMPORTANT TO READ THIS: At the end of the upgrade the Lock screen will appear frozen without the date and time for up to 10 minutes. Please be patient and let it sit – eventually the date and time will appear and it will allow you to unlock your phone. There is a post-upgrade migration status screen missing, which normally would show you that it was making progress. If you get impatient and restart or mess with locking/unlocking your phone, you’ll wind up in a funky state – so just relax and let it do its thing.

Build 10136 Known issues:

  • After upgrading, you will still see duplicate tiles for apps like Search and Phone under All Apps.
  • If you have too many PIN unlock attempts, you’ll see the “enter A1B2C3” reset experience. However, there is an issue in this build where after you enter the code you won’t see the PIN pad. The workaround is to press Emergency Call after entering the code, then press Back and you’ll be able to enter your PIN.
    • We recommend disabling the double-tap-to-wake feature on some Lumia devices by going to the Settings app then Extras > Touch > Wake to prevent any accidental PIN unlock attempts.
  • There is an issue that may cause Skype not to work after upgrade. The best workaround is to uninstall Skype on Windows Phone 8.1 *before* you upgrade to this build and then reinstall it after upgrading. If you miss that step though, you can usually resolve by uninstalling it and reinstalling from the Store once you’re on 10136.
  • If you’re having issues installing new Language Packs in this build, see this forum post.