Nexus 5 full disk encryption stuck 12 hours in? I have loved my Nexus 5 since it was released with KitKat, and last evening I decided to enable full disk encryption, which I expected might take around an hour or so.  It's now about 12 hours in with no visible change.  All I see are the Marshmallow four animated dots.  I've never seen any progress display on encrypting the disk, and of course I'm trying to avoid rebooting the phone for fear that the disk will be a jumbled mess and I could either lose my data or even brick the phone.

What is the best course of action at this point, and possible consequences?
Could it be that your device is rooted? If yes, google a bit, there are some tutorials which could help. 
In that case killing or deactivating SuperSU (or similar) could bring success.

Here is what sometimes seem to work (answer is from aikidork):


Install Busybox (I have Stericson version), RootExplorer file manager, a terminal Emulator (or enable USB debugging), and SuperSU (no promises about this working on other root managers!)
Set up a fingerprint lockscreen. Configure ALL your fingers you want to use ahead of time since this won't be configurable later!
Using Root Explorer, copy/backup the following files to external SD:

/data/system/locksettings.db ,

/data/system/locksettings.db-shm , 

/data/system/locksettings.db-wal
Kill all running apps.
Launch command prompt in ADB or Terminal Emulator.
Execute su so that your prompt changes from "$" to "#" (you are now root)
Kill the SuperSU daemon to temporarily disable root mode (lasts until reboot): 

pkill -KILL daemonsu
Your root daemon will kick you out of privileged status during shutdown, changing "#" prompt back to "$" (root is temporarily disabled).
DO THIS STEP IMMEDIATELY without rebooting or launching more apps!
Go to the default security screen and select Encrypt Device. Set up
a password lock screen as required (8 digits with at least one
number). Plug in to power if not using ADB. Confirm the encryption
operation.
If everything is working well, you will see the encryption screen,
 a soft-reboot splash screen, and then a progress indicator counting
 up to 100%. If it moves beyond zero, congrats your encryption is
 working! Wait for this to finish.
Now, to restore the lock screen, unlock the phone and launch your
 Root Explorer again.
Restore the three files you backed up earlier to their exact
 locations, overwriting the replacement ones that the encryption
 setup created.
Wait for phone to lock (or reboot once more) and confirm that you
 can unlock the phone with fingerprint.


PS: I currently have the same problem but none of the mentioned solutions helped so far.

UPDATE: This seems to be a common issue when an app is still holding open files. However, there is no official way to determine which process is causing these issue so far and it is recommended to have a chat with the support.