Evolution slow start when DBUS_SESSION_BUS_ADDRESS is set

[Chris G]

If I try and start Evolution in an environemnt where the variable
DBUS_SESSION_BUS_ADDRESS is set then it takes 30 seconds to start and I
get the following error:-

    ** Message: secret service operation failed: Did not receive a reply.
    Possible causes include: the remote application did not send a reply,
    the message bus security policy blocked the reply, the reply timeout
    expired, or the network connection was broken.

If I simply unset the variable before starting evolution then it starts
almost instantly.

The trouble is that DBUS_SESSION_BUS_ADDRESS *is* set when I start
evolution from any of the menus so I always get the delay.  The only way
I can avoid it is to start evolution from a command prompt. where
DBUS_SESSION_BUS_ADDRESS isn't set.

Can anyone suggest why having DBUS_SESSION_BUS_ADDRESS is causing this
delay and/or any sort of workaround?

-- 
Chris Green