Why my Fedora 26 is not unmounting /home?

Question

I just upgraded to Fedora 26. Everything is working fine, except for a strange umounting problem at shutdown: /home and Temporary directory partitions are not being umounted. This is the boot message:

....
Jul 12 21:55:46 Orion systemd: Unmounting /home...
Jul 12 21:55:46 Orion systemd: tmp.mount: Mount process exited, code=exited status=32
Jul 12 21:55:46 Orion systemd: Failed unmounting Temporary Directory.                   <===== THIS
Jul 12 21:55:46 Orion systemd: home.mount: Mount process exited, code=exited status=32
Jul 12 21:55:46 Orion audit: SERVICE_STOP pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=systemd-fsck@dev-disk-by\x2duuid-786e5bbf\x2d0527\x2d4e71\x2daf31\x2d78cf5d8e3038 comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Jul 12 21:55:46 Orion systemd: Failed unmounting /home.                                 <===== THIS
Jul 12 21:55:46 Orion systemd: Stopped File System Check on /dev/disk/by-uuid/786e5bbf-0527-4e71-af31-78cf5d8e3038.   <===== THIS IS \home
Jul 12 21:55:46 Orion systemd: Stopped target Swap.
....

I did a lsof /home before shutdown, and I get some pulseaudio activity and a autologin script in \home. Neither ever gave any problem before. Temp stuff is irrelevant, but I am afraid that \home may be unproperly umounted and eventually corrupted.

Clues?

Answer 1

I found that uninstalling plymouth (for fedora: dnf remove plymouth* && dracut --force) fixed a similar issue for me. I had the same error but also noticed that the first (visible) message was a failed to start plymouth. After that the system had trouble umounting tmp and home but also shutting down gdm and other services. It would take about 5 minutes to shutdown or reboot.

Not sure why plymouth wouldn't start as I found no trace of this error in my logs.