We are using a free java based RDP client for fall back, works fine on Macs and in Chrome and Firefox on windows. I am working on a mac book that has 10.8.5 for the OS, Safari is 6.05, java is current 8u25 version. What we usually need to do to have it work in current OSX versions is to add our IVE address to the Java Security exception list, as OSX doesnt like the certificate associated with the free RDP client we are using (Elusiva).
Any idea why I am getting the "This terminal session is not supported on your computer" when trying to start the RDP session? The only time I have seen it before is in really old versions of OSX, like 10.6. I turned on the java console, but when I click on the bookmark, the java console doesnt come up, just the error message immediately, which makes me wonder if Safari or OSX has already decided this is unsafe, so it doesnt even let java get started.
I tried resetting Safari settings but just continue to get that error message when the RDP bookmark is clicked.
I ran into a similiar situation recently.
I found that if Network Level Authentication (NLA) is enabled on the server, it will fail because the Java client doesn't support NLA.
Dave, is this a user defined RDP bookmark or a server assigned RDP bookmark? Unless something has changed, user defined RDP bookmarks will always attempt to use the Juniper Win32 RDP appled which will not work for Mac - hence the message.