Which operating system are you using?
Mac OS X Lion 10.7.4(11E53)
Ok since this is Acrobat on Mac OS you will not be able to simply install the trial. Instead lets first try rebooting in safe boot and logged in as a Root user and try installing again. Please feel free to respond if you need additional details on how to complete either of these actions and I will locate the appropriate Apple technical document.
Yes I have tried that several times and that didnt work as well.
Ok and you did log in as root and saw Welcome to Mac OS X Safe boot?
If so we will try the longer solution which seems to have lead to success for many users. Please complete the following steps:
- Remove all Adobe Creative Applications using the uninstallers located in Applications/Utilities/Adobe Installers
- Run the clean up utility directions can be found at CS Cleaner Tool for installation problems | CCM, CS6, CS5.5, CS5, CS4, CS3 - http://helpx.adobe.com/creative-suite/kb/cs5-cleaner-tool-installation-problems.html
- Reboot in Safe Boot in the Root User account
- Download the Adobe Application Manager from https://creative.adobe.com/
- Download and install any Adobe Creative application besides Acrobat
- Download and install Adobe Acrobat
- Open the Adobe Creative application download previously
- Open Adobe Acrobat
Please feel free to respond to this thread if you have any questions about any of these steps. I would recommend completing them in full as several users have reported success by following these directions.