Chosen Solution

For some reason, my iMac will only boot up in safe mode. If I turn it on without holding the shift key I will get the Apple logo for a few seconds and then the cirlce with a line through it. Background: We are still running Snow Leopard on this system. We have been having issues at start-up but doing a PRAM reset for 3 chimes always yielded back to normal. Seemed like we had to do this a lot. I try not to shut it down. I did run the disk utility and after a few minor repairs to the disk the system would boot up fine. But, then again, we don’t shut it down often. Knowing we needed to be on the newer system for security reasons we purchased a new MacBook Pro 13" with dock and 27" monitor to replace the iMac. So I shut it down the iMac to move it to the other desk as a backup and that is when the system would not start up in normal mode. I still need to have this computer around to run old software that the new system will not run. Such as Freehand. We have a ton of old designs and files done in freehand. Things I have tried: PRAM resetSMC reset Command R doesn’t do anything otherwise I would restore the time machine backup Holding down option at startup does not do anything but give me the internal disk as a choice.

The error you’re seeing is called the ‘Prohibitory symbol’ As you are able to get the system to startup in Safe Mode I’m suspecting the dedicated GPU drivers are messed up somehow or not being accessed. About the screens you see when your Mac starts up Given the systems age and the fact you mostly leave the system plugged in, I’m suspecting the PRAM battery is dead. This can explain whats happing. It kept loosing its settings and now it’s fully dead.

Let’s replace it that should resolve your problems. Sadly, in this series, the battery is on the backside of the logic board. So you’ll need to fully remove it. Here’s a good vid explaining how to get it out and if you stop at 26:15 the presenter points out the battery: Late 2009 iMac 27" Video Card Repair He goes into repairing the GPU card which we don’t need to deal with here.

I don’t know about fixing the machine, but to get the files off the drive you could try putting it into TARGET mode.