Who has updated the Samsung Galaxy S6 to the new Android Marshmallow 6.0.1 and is a user of the fingerprint sensor for unlocking the lock screen, will now have the following peculiarity:
Then the Samsung Galaxy S6 restarts, the following message appears on the display:
"Enter PIN instead of using fingerprint recognition after restarting device to protect fingerprints"
This means that you cannot unlock the Samsung Galaxy S6 with the fingerprint. But you must enter the previously set pin. This phenomenon appears with Android Marshmallow 6.0.1 after each reboot of the device.
After the pin input the smartphone can be unlocked as usual by fingerprint. Now you may wonder whether you can disable this feature on the Samsung Galaxy S6?
The answer is "No".
Since it is a security feature, it is not possible to unlock the Samsung Galaxy S6 after a restart without the input of the pin or only by fingerprint. Perhaps this will be reversed in one of the next firmware updates, for the time being, however, it remains with this setting.
You know now why after a restart of the Samsung Galaxy S6 this cannot be unlocked by fingerprint, but only with a pin.