Some of our beta testers have thankfully pointed out to us that we forgot to mention a tiny, yet important, detail: Currently, Mendeley Desktop only runs on Windows. Sincerest apologies to those Mac and Linux users who downloaded our software only to discover that their operating system was not yet supported!
We feel a little stupid now for not having communicated this before – a classic case of overlooking the obvious. However, we are working hard on porting the code to run properly on Linux and Mac OS X and other architectures. In the meantime, you can run Mendeley Desktop on these platforms using a virtual machine (such as Parallels or VMware) or by using the free Wine (on Linux) or Darwine (on Mac OS X) which do not require a virtual machine or a Windows license.