Please enter passphrase for disk Crucial_CT250MX200SSD4 (cryptswap1) on none! 
update-initramfs: deferring update (trigger activated)

Broadcast message from root@username-XPS-13-9343 (Thu 2015-04-30 22:06:22 EDT):

Password entry required for 'Please enter passphrase for disk Crucial_CT250MX200SSD4 (cryptswap1) on none!' (PID 4027).
Please enter password with the systemd-tty-ask-password-agent tool!

查看swap分区

sudo fdisk -l 

[sudo] password for kempe: 

 Disk /dev/sda: 233,8 GiB, 251000193024 bytes, 490234752 sectors 

Units: sectors of 1 * 512 = 512 bytes 

Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes

 Disklabel type: gpt
Disk 

identifier: B59D4149-AC8E-4B71-B51F-8926B2E82C14 

 Device         Start       End   Sectors   Size Type 

/dev/sda1       2048    409599    407552   199M EFI System

 /dev/sda2     409640 253319775 252910136 120,6G Apple HFS/HFS+ 

/dev/sda3  253321216 269320191  15998976   7,6G Linux swap 

/dev/sda4  269320192 490233855 220913664 105,3G Linux filesystem

找到swap分区在/dev/sda3上

关闭swap分区

sudo swapoff -a

禁用swap加密

sudo cryptsetup remove /dev/mapper/cryptswap1

sudo vim /etc/crypttab

sudo /sbin/mkswap /dev/sda3 

sudo swapon /dev/sda3

sudo vim /etc/fstab

替换/dev/mapper/cryptswap1为/dev/sda3