liu-xiao-guo@localhost:~/apps$ snap change 92
Status  Spawn                 Ready                 Summary
Undone  2016-10-14T11:51:46Z  2016-10-14T11:54:24Z  Stop snap "lights" services
Done    2016-10-14T11:51:46Z  2016-10-14T11:54:24Z  Make snap "lights" unavailable to the system
Error   2016-10-14T11:51:46Z  2016-10-14T11:54:24Z  Remove security profile for snap "lights" (x1)
Done    2016-10-14T11:51:46Z  2016-10-14T11:54:24Z  Remove data for snap "lights" (x1)
Hold    2016-10-14T11:51:46Z  2016-10-14T11:54:24Z  Remove snap "lights" (x1) from the system
Hold    2016-10-14T11:51:46Z  2016-10-14T11:54:24Z  Discard interface connections for snap "lights" (x1)

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Remove security profile for snap "lights" (x1)

2016-10-14T11:54:24Z ERROR cannot find installed snap "lights" at revision x1

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Remove snap "lights" (x1) from the system

2016-10-14T11:51:49Z ERROR cannot remove snap file "lights", will retry in 3 mins: umount: /snap/lights/x1: not mounted