Hard Reset your O+ 8.52 and remove password, pattern lock and gmail account
Hard resetting / factory resetting your phone will solve the following issues:
1. If you forgot your pattern lock
2. If you forgot your gmail account
3. If you forgot your password
4. Apps that automatically force closing
5. Stuck in O+ Logo (sometimes does not work if the firmware is totally damage)
NOTE: Performing hard reset will erase your data.
To hard reset:
1. Turn off your phone.
2. Press and hold first the POWER Button, then immediately press and hold the VOLUME UP. Keep pressing the button before the O+ logo appear.
3. An Android Logo will appear
4. Press Home button to active the Android System Recovery
5. Select wipe / factory reset, press Volume rocker to navigate and press the Option Key (left capacitive key) to confirm your selection
6. Reboot your phone.
Reference Video To hard reset
I hope this tutorial helps you.. If you have any question just drop a comment.