Windows 8 pro - Remote Desktop will not /span multiple monitors

I have a windows 8 pro PC with dual monitors (one is a notebook).  When I run MSTSC with the /span option it will not display across both monitors.  When I use this same setup only on a Windows 7 PC it works fine.  I have also tried the /multimon and it does the same thing.

I have also modified settings in the .RDP file.
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Randy DownsOWNERCommented:
Maybe this will help

I have Windows 8 Pro and I can confirm that it supports discrete multiple monitor RDP session. I initiated the RDP session from my other Windows 7 PC by using the following command

mstsc /multimon


That is great but how about having 2 out of 3 monitors enabled for RDP.

Right now I must confirm that configuring multimon locally, or changing max monitors in group policys, or configuring RDP host server on client settings tab regarding max monitors does not work at all.

I see that this is a big issue for many who use 3 monitors. Whatever setting you change, you always will get just one monitor or all three. Clearly it does not work so please no advice how to change these settings.
AndyZookAuthor Commented:
Tried it.  No help.
Randy DownsOWNERCommented:
OK maybe this will work

if you run (win+R) mstsc /?, it will show you /multimon.  If you run simply "mstsc" or click the "Remote Desktop Connection" icon, click the "Show Options" button, then go to the Display tab.  There is a check box that says "Use all of my monitors for the remote session".

I have tested both Win 8 Pro & Win 8 Ent with the /multimon and it checks that box, and opens RDP sessions across my three monitors.  Also manually checking that box works.
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AndyZookAuthor Commented:
Ok.  I resolved the issue.  In Windows 8 (unlike Windows 7) for the /span option to work both monitors MUST have the same resolution.  Nice downgrade Microsoft!

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Randy DownsOWNERCommented:
Glad you figured it out
AndyZookAuthor Commented:
It solved my problem.
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