I have the latest Yosemite insist (iMac Late 2009 ) and have tried everything from instructions found on the web :
* Resetting memory
- Recovery mode
* Reinstallation Yosemite
- Hard disk controlled via disk utility : not to find errors
- Try to boot from a bootable USB stick
The problem remains: the Mac boots but remains on the progress bar (after the apple ) hang around half.
I do not have a backup via Time Machine .
Does anyone know what can be done please?
Thank you already .
Mario Mewis .
edit: According to the Internet there are many people with this problem with this series iMacs. Probleembij probably lies the ATI Radeon 4850 graphics card ..