Hello Windows 10 users!

After we posted the first article Known issues on Windows 10 Mobile build 10051 & How to fix them, we’ve received many positive feedback from you & the problems you face. Now we list here the most common issues when using Windows 10 build 10051 for phones. These issues will be sent to Microsoft Engineers, who are working hard on perfecting Windows 10. If your problem is not listed here, please inform us via the comment section below.
Known issues on Windows 10 Phone build 10051 & How to fix them

Problem found by HIMEL ROY
Windows 10 is awesome i agree. But only thing my mobile face is not disabling mobile data

Problem found by Ahmed Nauman Tariq
I have a Lumia 520. After updating my phone to windows 10 (maybe version 10.0.12534.56), the Settings won’t open.
Though I am able to open a particular setting by holding that one in ‘quick settings’ e.g. WiFi or Rotation lock etc. But all settings won’t open, either from All Apps, start screen or which settings. And thus I can neither change my UI settings, nor check for any updates to get a fix for the problem.
Any help would be appreciated.

Answer:
Thank you for being a part of Windows 10 Technical Preview.
As an initial troubleshooting steps, I would suggest you to do the 
soft reset of the Windows Phone. Once you do the soft reset of the Windows Phone check if you are able to use app settings.
Let us know the update after you try the above steps.


Problem found by Apratim
1> Notification in collapsed mode at times show a horizontal line going through the icons on Lumia 920.
2> Camera Preview garbled and pushed to a thin strip towards the right of screen in portrait mode and top of screen in landscape mode. Can see five previews in the thin strip each  showing similar garbled data.
3> Phone was in Flight Mode during update, after that not able to get out of Flight Mode even after couple of resets. May be similar problem to SIM not detecting.

Problem found by Hari
Notification bar can’t be pulled up still persist after following up your idea.

After updating lumia 535 most of the applications not working also once quick access open we phone will not return to menu by swapping or pressing back button ………..phone getting hang also need to reset power to use it again

Answer:

Sorry to know that the Notification bar is not working after installing the latest build on the Windows Phone.
Please try restarting the phone and check if that helps fix the issue. Else, try resetting it.
Important: Take a backup of all important data.
If it fails, use the Windows Phone Recovery Tool to return to Windows Phone 8.1. This means all your personal content will be erased, and your phone will be restored to the latest version of Windows Phone for your specific device. You’ll have an opportunity to restore a backup while you’re setting up your phone again, but app data and settings may be lost after you restore.
Let us know the result. If you have further queries, we will be happy to help.

Problem found by Johannes Pekki
sorry my shitty english. my win 10 cant update (security updates) because my Network is invoiced. how can i change that?

Problem found by Lucien Henrioulle
Problem with updating to build 10061 professinal must act as a administrator system

Answer:
Problem found by Musa
Possible to install Windows 10 on Android? using Galaxy S3 ATM

If any problem does not have an answer, please be patient. Microsoft Engineers are working hard to solve it. 
If your problem is not listed here OR you find the way to fix above issues, please inform us via the comment section below.