I downloaded the installer for Prism Mac, but when I double click I get a message: 'no mountable file systems'.

The installer for Prism Mac 5 comes as a DMG file. You 'mount' this file like a disk drive to run the installer. This is the standard way to distribute downloadable software for Macs.

The message about no mountable file systems can come up in these situations:

Disk permissions are damaged

This is a common problem on Macs that leads to lots of strange problems.  Easy to fix:

1. Launch Disk Utility located at: "[system disk]:Applications:Utilities:Disk Utility"
2. Once inside the Disk Utility window, select your hard drive (not  the program CD or downloaded DMG 'drive').
3. Go to the First Aid tab
4. Click the Repair Disk Permissions button. 
 

This will almost certainly fix the problem. If not, read on...

OSX too old

The message suggests that you have an old version of OSX. Regardless of installing issues, Prism 5 Mac requires OSX 10.4 (Tiger) or 10.5 (Leopard). It may also run OK on 10.3 (Panther) but we haven't fully tested that.  The message about 'no mountable file systems' suggests you have an earlier version of OSX.

Download incomplete

The download of the dmg file may be incomplete or damaged. Delete it and download again. If  you are downloading a purchased Prism (rather than a demo) and the server says you have already downloaded it, write to sales at graphpad.com and we can reset the server.

 You are not logged on with admin rights

1. Open system Preferences from the Apple menu.
2. Select Accounts.
3. In the list of users in the Accounts window make sure the current user is selected (should be selected by default).
4. Click the Edit User button.
5. In the opened window (sheet) make sure that the check box "allow user to administer this computer" is checked.
6. If this checkbox is grayed out, you will need to log in as Administrator.