Missing Ubuntuone sync indicator

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/1299313

This is not a bug in xfce4-indicator-plugin. The way how the different indicator services are started has changed (bug 1185565).

Please add "INDICATOR_ALLOW_NO_WATCHERS=yes" to /etc/environment and restart the session. Does this resolve the problem for you?

Unfortunately no. The sync indicator still does not display.

Does indicator-sync-service appear in the list of currently running processes?

No it doesn't. Manually starting it up generates this message:

toz@tahrX:~$ /usr/lib/i386-linux-gnu/indicator-sync/indicator-sync-service
(process:14075): libindicator-WARNING **: No watchers, service timing out.
(process:14075): libindicator-WARNING **: blocked by environment variable.

I then unset the INDICATOR_ALLOW_NO_WATCHERS variable and tried re-running and got this message:

toz@tahrX:~$ unset INDICATOR_ALLOW_NO_WATCHERS
toz@tahrX:~$ /usr/lib/i386-linux-gnu/indicator-sync/indicator-sync-service
(process:14786): libindicator-WARNING **: No watchers, service timing out.
(process:14786): GLib-CRITICAL **: Source ID 11 was not found when attempting to remove it

Have googled a bit but haven't found anything relevant yet.
Have tried puring and reinstalling indicator-sync to no effect.
I appear to have the necessary ubuntuone and indicator-sync packages installed:

toz@tahrX:~$ dpkg -l | tr -s " " | cut -d' ' -f2,3 | grep ubuntuone
python-ubuntuone-client 13.10-0ubuntu2
python-ubuntuone-control-panel 13.09-0ubuntu2
python-ubuntuone-storageprotocol 13.10-0ubuntu3
ubuntuone-client 13.10-0ubuntu2
ubuntuone-client-data 13.05-0ubuntu1
ubuntuone-control-panel 13.09-0ubuntu2
ubuntuone-control-panel-qt 13.09-0ubuntu2
toz@tahrX:~$ dpkg -l | tr -s " " | cut -d' ' -f2,3 | grep indicator
gir1.2-appindicator3-0.1 12.10.1+13.10.20130920-0ubuntu4
indicator-application 12.10.1+14.04.20140324-0ubuntu1
indicator-messages 13.10.1+14.04.20140321-0ubuntu1
indicator-power 12.10.6+14.04.20140328-0ubuntu1
indicator-sound 12.10.2+14.04.20140324.is.12.10.2+14.04.20140320-0ubuntu1
indicator-sync 12.10.5+14.04.20140207-0ubuntu1
libappindicator3-1 12.10.1+13.10.20130920-0ubuntu4
libindicator3-7 12.10.2+14.04.20140304-0ubuntu1
xchat-indicator 0.3.11-0ubuntu4
xfce4-indicator-plugin 2.3.2-0ubuntu1

Ubuntuone-syncdaemon is running (files are syncing):
toz@tahrX:~$ ps -ef | grep ubuntuone | grep -v grep
toz 2163 1750 0 10:54 ? 00:00:03 /usr/bin/python /usr/lib/ubuntuone-client/ubuntuone-syncdaemon

Attached is an strace output of running indicator-sync-service (if its helpful).

It works fine here, sync indicator is not missing.

thad@local:~$ /usr/lib/i386-linux-gnu/indicator-sync/indicator-sync-service
(process:21808): libindicator-WARNING **: No watchers, service timing out.
(process:21808): libindicator-WARNING **: blocked by environment variable.
(process:21808): GLib-CRITICAL **: Source ID 11 was not found when attempting to remove it

I still doubt that this is some bug in xfce4-indicator-plugin.