HTC also have an issue related to screen, If your Htc U11 stuck on HTC screen then there are some ways which can help you get out from this situation, what you need to do is to follow below points carefully and you can easily solve this type of problems.
Best suggestion is Restart your Android Mobile phone if you unable to restart then
If battery is not inbuilt then remove the battery and insert again
If the battery is inbuild then recharge your phone and try again after 5 min.
Remove your memory card, sometimes battery is also responsible for this type of problem
Remove all unused apps and apps that eat a lot of memory.
Turn Off data and wifi,
Use vol+ power which simulates a battery pull and then as soon as the screen powers down immediately vol- power which will bring you to the bootloader screen, then you can reset or go to recovery from there.
If your problem still exists then follow below suggestion.
Also read – Soft Reset HTC U11
If you are facing this type of problem again and again then hard reset your phone, but make sure you backup all data.
Share your Mobile model number if you face a similar type of problem.
How to Factory Reset HTC phones
1. Press and hold Volume Down button and press once the Power button and keep holding Volume Down button.
2. Bootloader mode will open. Scroll down, find Recovery option and select it.
3. Inside Recovery, select Wipe Data and select Start.This will hard reset your HTC One M8.
Use Dropbox or google drive to backup your data regularly.