Finally, Windows 10 Technical Preview build 10051 has launched, and as before, it contains a number of errors that you should pay attention to. Perhaps the most serious fault is Camera roll will not automatically upload to OneDrive, so you should check it regularly and perform manual backups to ensure no data loss. Office Hub has been removed from the build today so you will not be able to open Word, Excel, PowerPoint and OneNote. The company said that in the next few weeks the new Office in the form of universal app will be released to fix this. Please have a look on the details listed below.

See How to update Windows Phone 8.1 to Windows 10 Build 10051?

How to fix problems in Windows 10 Build 10051?
How to fix problems in Windows 10 Build 10051?

    1. There might be situations in which auto-upload of your Camera Roll to OneDrive may not be working. Please be sure to back up your photos especially if you need to use the Windows Phone Recovery Tool to go back to Windows Phone 8.1.

    2. The Office Hub has been removed from this build. You won’t be able to open Word, Excel, PowerPoint or OneNote files in this build. Preview versions of the universal Office apps will be available in the coming weeks.

    3. All Bluetooth-based interactions with Cortana are not working in this build because we’re reworking how Cortana interacts with Bluetooth. This includes dictating and reading text messages, initiating searches and chit-chat, and all system-level control (such as playing music, launching applications, or navigating settings.

    4. After upgrade, some apps that have been installed onto a SD memory card will fail to launch. To fix this, uninstall and reinstall the apps.

    5. About 1% of the time, incoming phone calls may not play a ringing sound.

    6.Call + SMS filtering will not work after upgrade.

    7.For people upgrading their phone from Build 9941, there is a bug in which your phone’s MMS settings will be lost after upgrade. The new Messaging app doesn’t yet have the ability to re-enter these settings. You will need to use the Windows Phone Recovery Tool to go back to Windows Phone 8.1 and then upgrade to this build to get MMS working again.

    8. Also for people upgrading their phone from Build 9941, the tiles on your Start screen for the Camera and Photos apps may be missing or corrupt. You will have to unpin any corrupt tiles and re-pin the apps to your Start screen.

    9. On some phones, due to a scaling bug the dismiss button won’t be visible when an alarm is triggered. To stop your phone from “alarming “just touch the arrow and swipe up on the notification and off the screen to end the alarm.

    10. On phones with 512MB of memory, apps can randomly crash due to an issue with memory management.

    11. Flight mode cannot be enabled.

    12. Data connections can’t be disabled.

    13. You may need to re-pin the Phone app after upgrade.

    14. The Insider Hub is now included on Phone but may fail to launch on some phones.

      There were several other bugs in the previous build which had no workarounds, such as apps not being displayed in Battery Saver mode and VPN settings failing to launch. The absence of resolutions for these issues may annoy some users, but Microsoft is no doubt striving to eliminate such problems in future builds. .
      Are there any other issues that have been fixed or you would like to see fixed in the Windows 10 Technical Preview for phones? Let us know in the comments section below.