Comment 3 for bug 1159707

I'm also experiencing this on Arch Linux. After running

cinnamon --replace &

I see the following output:

Window manager warning: Log level 16: Unable to register authentication agent: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: An authentication agent already exists for the given subject
Window manager warning: Log level 16: Error registering polkit authentication agent: GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: An authentication agent already exists for the given subject (polkit-error-quark 0)
      JS LOG: Cinnamon started at Sat Apr 27 2013 06:59:04 GMT-0500 (CDT)
Window manager warning: Log level 16: STACK_OP_REMOVE: window 0x63 not in stack
Window manager warning: meta_window_activate called by a pager with a 0 timestamp; the pager needs to be fixed.
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
failed to create drawable
    JS ERROR: !!! WARNING: 'assignment to undeclared variable i'
    JS ERROR: !!! WARNING: file '/usr/share/cinnamon/js/misc/windowUtils.js' line 54 exception 0 number 156

(the JS ERRORs occurred when I Alt+Tabbed to Chromium)

Closing windows at random seems to fix the problem, but it's never the same window that does it.