Sometimes the HTC One M9 will have a black screen after you have turned on the smartphone. The problem is that the HTC One M9 buttons light up like normal, but the screen remains black and nothing is showing up. The HTC One M9 screen won’t turn on at random times for different people, but the common problem is that the screen fails to wake up. There are several different ways to try to solve the HTC One M9 blank screen problem, follow the instructions below to learn how to fix the HTC One M9 black screen not turning on issue.
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Boot to Recovery Mode and Wipe Cache Partition
The following steps will get the HTC One M9 into Recovery Mode by booting the smartphone:
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- Press and hold the Volume Up, Home, and Power buttons at the same time
- After the phone vibrates, let go of the Power button, while still holding the other two buttons until Android System Recovery screen appears.
- Using the “Volume Down” button, highlight “wipe cache partition” and press the Power button to select it.
- After the cache partition is cleared, the HTC One M9 will reboot automatically
Read this guide for a more detailed explanation on how to clear cache on the HTC One M9 
Factory Reset HTC One M9
If the method above didn’t help you fix the black screen problem on the HTC One M9, then you should try to factory reset the smartphone. The following is a guide on how to factory reset the HTC One M9 . It’s important to note that before you go to factory reset a HTC One M9, you should back up all files and information to prevent any data from being lost.
Get Technical Support
If none of the methods have worked in trying to get the HTC One M9 to turn on with the blackscreen, it’s suggested to take the smartphone back to the store or to a shop where it can be physically checked for any damage. If proven defective by a technician, a replacement unit may be provided for you of it could be repaired.