Need to change Yosemite to Mountain Lion for Pro Tools 10.3.10.
Requires OS 10.8.5 and also need it for Waves RTAS plug-ins. Have OS on a USB plug. Can't erase HD clean enough to boot into Mountain Lion. Continues to boot into Yosemite.
Running Mountain Lion on an iMac Mid-2010 vintage into Pro Tools 10.3.10 w/003+ rack without any problems.
-wayne
iPad Mini, OS X Yosemite (10.10.5), Change to OS X Mountain Lion (10.8.5
You would need to completely erase the drive to be able to install Mountain Lion. You can't uninstall an OS X version. You need to erase and re-install the older version. That's where your backup comes into play.
FWIW, your Mini must be a 2012 or older to use Mountain Lion.
If your Mini is a new 2014, it cannot run any operating system
earlier than Yosemite because there is no support for it in the
older operating systems.
I mention this since you did not state what model Mini you have.
I don't know if you solved this or not but one way that should work as it did for me is by accessing the Mac you want to install/reinstall ML on via and older machine that is running ML or earlier via Target mode. I have kept my 1st gen Macbook for that purpose, if you don't have one maybe you can borrow one for this purpose.
Make sure the ML Installer is on that older machine & connect the two machines together (FW or usb) with the destination machine powered off then power it up while holding the "T" key to force it to start in Target mode (if you have no experience of this then google Target Mode on a Mac) Now you should be able to do a clean install of ML onto your mac mini. Good luck!
dave
The only answer that makes sense is Woodmeister. It is absolutely paramount to know if your mac was delivered with Mountain Lion or earlier. If not, you cannot go back to ML.
Change OS 10.10.5 to OS 10.8.5(Yosemite to Mountain Lion
