Can I restart my Mac remotely via screen sharing if the screen shows only linen? I am currently in Norway.  My Mac mini is in my apartment in Australia.  I can access screen sharing via Back To My Mac.  It connects fine, but the screen has only linen - no menu bar, no dock, no anything else.  I am fairly sure that is what is actually on the screen and that it isn't a problem with the connection or anything like that (it's happened once before while I was sitting in the same room...)

I know the system is responsive because the one other thing that can poke through my router is the Transmission web interface, and that works just fine.  (Unfortunately I seem to have neglected to forward a port for ssh...)

Is there any way I can reboot or otherwise regain full use of the system via the limited screen sharing access that I have?
So apparently you can use the Back To My Mac infrastructure to get to SSH even if there's no port open on the router in front of the relevant Mac:

Find your iCloud account number by executing this command in terminal:

dns-sd -E


Example output

Looking for recommended registration domains:
Timestamp     Recommended Registration domain
23:45:15.660  Added     (More)               local
23:45:15.660  Added                          icloud.com
                                             - &gt; btmm
                                             - - &gt; members
                                             - - - &gt; 123456789


(Make a note of the number on the last line, in this case 123456789 (this is just an example).

The hostname you need to use for ssh is &lt;computer's local hostname&gt;.&lt;number above&gt;.members.btmm.icloud.com.  Replace spaces with hyphens, and omit apostrophes (the default name is "Name's &lt;type of Mac&gt;")

The command I used therefore was:

ssh -2 -6 Jons-mac-mini.123456789.members.btmm.icloud.com


To complete the solution to my problem (rebooting), once logged in via SSH, I used the following command to restart:

sudo /sbin/shutdown -r now


(Sourced from here)