Short version: the latest available version of MDX Studio can be downloaded from http://www.sqlbi.com/tools/mdx-studio/
Long version: Last week Stacia Misner twitted that the online version of MDX Studio was no longer available. It was hosted on http://mdx.mosha.com. It was a sad news, and it is also not good that nobody is maintaining the desktop version of MDX Studio. The latest release is the 0.4.14 and as I am writing it is still available on a SkyDrive link provided by Mosha Pasumansky, who wrote MDX Studio. Mosha does not work in Microsoft now and the entire BI community hopes that somebody will continue its work on this product. Unfortunately, it cannot be published on CodePlex because of some IP restrictions.
Only bad news? Well, I hope no. The first good news is that MDX Studio also works with Analysis Services 2012 in Multidimensional mode. The second news is that, after having checked that we can do that, we created a web page on SQLBI web site to download the latest available release of MDX Studio. I hope it will be necessary to update it in the future, by now it is just a way to simplify the finding and download of this precious tool, and to grant that it will not disappear in case the current SkyDrive using to host the download would be discontinued, like it happened to the MDX Studio online version.
Now a question to the BI Community: I know that there was some content available regarding tutorial on MDX Studio. I’d like to gather it and to put all in a single place. If you have such content, please contact me directly writing to marco (dot) russo (at) sqlbi [dot] com. Thanks!
UPDATE 2014-09-09 A refresh is now available with a fix for running with named instances and with Analysis Services 2014.