How to reset or unlock the lock screen on HTC One M8 without doing factory reset? I have an HTC One M8. I set up a lock pattern and now I can't remember it to unlock the device. Is there a way to unlock the device with out doing a factory reset? I tried the Android Device Manager but had no luck with that.
Using ADB

If you have access to an adb shell, you can try this:

adb shell rm /data/system/gesture.key


And just in case

adb shell rm /data/system/password.key


Using a (custom) recovery

If you have a custom recovery (otherwise look it up), you can flash Aroma File Manager or just use your recovery's file manager: 

With this, you go to /data/system and delete gesture.key and (if needed) password.key.

Hope this helps