forcefsck not working

My Ubuntu workstation believes it needs to fsck the root filesystem, but it will not.

run-parts /etc/update-motd.d/ | sudo tee /var/run/motd.dynamic

Welcome to Ubuntu 16.04 LTS (GNU/Linux 4.4.0-22-generic i686)

 * Documentation:  https://help.ubuntu.com/

0 packages can be updated.
0 updates are security updates.

*** /dev/sda1 will be checked for errors at next reboot ***

Last mounted on:          /
Last mount time:          Sun May 29 21:43:51 2016
Last write time:          Sun May 29 21:43:40 2016
Last checked:             Tue Oct 27 01:51:27 2015

.... but when I power on the machine again, I get a waing that ruing e2fsck is recommended, instead of it actually ruing e2fsck. The '/forcefsck' file is missing after a reboot.

[   15.365778] EXT4-fs (sda1): waing: checktime reached, ruing e2fsck is recommended

What else am I overlooking? previous threads in the forum about this problem date back to 2012 and 2008, and usually advise "touch /forcefsck; reboot" or say that the problem goes away after installing some new keel packages (new for 2012). I'm not sure what else to do except boot from a CD-ROM and run fsck from an entirely discoected OS.