blank desktop at login

Status changed to 'Confirmed' because the bug affects multiple users.

Likewise, with a "fresh" install of Saucy, up to date as of 9th Oct 2013, the same thing happens.
/var/log/syslog shows JS errors saying that dbus couldn't be found in the search path.
This appears to be the same as the upstream bug:

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=718552

Triaging this. The error that Tom mentioned is actually showing up in my ~/.xsession-errors, not my syslog. Looks like Debian has already fixed this by porting to GDBus, although I haven't confirmed that.

Hello Clearflower, or anyone else affected,

Accepted cinnamon into saucy-proposed. The package will build now and be available at http://launchpad.net/ubuntu/+source/cinnamon/1.7.4-2ubuntu4.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

cinnamon does indeed start after installing the -proposed (1.7.4-2ubuntu4.1).

It is still not usable due to that other error (only launchers in the panel work, clicking on any other applet hangs the desktop, and no mouse and keyboard events are delivered to the applications).

Anyway this particular bug looks fixed, updating the tag.

I opened Bug #1248414 for the problem of keyboard/mouse input not working after you click menu or other panel applet.

I have the same experience that Eugene mentioned.
After installing the proposed package there exists bug with hanging desktop.

This bug was fixed in the package cinnamon - 1.7.4-2ubuntu4.1

---------------
cinnamon (1.7.4-2ubuntu4.1) saucy; urgency=low

  * debian/patches/port-to-GDBus.patch: Grab patch from Debian to port to
    GDBus and fix blank screen on launch (LP: #1180638).
 -- Logan Rosen <email address hidden> Thu, 17 Oct 2013 17:53:18 -0400

The verification of this Stable Release Update has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regresssions.