Question:

After updating my phone to Android T OS, my lock screen password isn't working correctly. What should I do?

Answer:

In Android S OS devices, the lock screen password can be set using both letters and numbers up to 16 characters long. When updating to Android T OS, this limit was increased to 256 characters. However, if you set a password longer than 16 characters on an Android S OS device, it would still only save the first 16 characters due to its limitations.

When entering a password longer than 16 characters during setup, the device would display a warning stating that only the first 16 characters will be saved. So, when trying to unlock your phone using a password longer than 16 characters on Android T OS, it won't work because the saved password is only 16 characters long.

To fix this issue, simply try entering the first 16 characters of your original password to unlock your phone. Once unlocked, go to Settings > Security and reset your lock screen password to a new one containing 17 or more characters specifically on your Android T OS device.