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I have a 2008 Mac pro and after awhile when trying to boot back up it would show the apple logo but with distorted green pixels inside the apple. It loads about halfway then shuts off and never fully boots up. I'm wondering if its just a GPU issue or if theres more going on with it before I spend money on parts to bring it back to life that dont even work.
Mac Pro, OS X 10.11
The initial "chime" sound is generated in software when your Mac passes the Power-On Self Test. If it occurs and/or startup continues, your Mac is working. The blank gray screen should light up. If the picture is distorted, you may have a graphics card problem as well. Then on to the disk Drive.
Accessing the Boot drive:
The solid Apple is not in the Mac's ROM at Cold start. The Apple logo can only appear when it is fetched in the first "blob" of software loaded from a 'magic' place on the boot drive, or re-run after a Restart. Then a whole lot of stuff is initialized, and the progress Bar moves part way across. After a cold start, seeing the solid Apple appear says your drive is not completely dead.
Mounting the Boot drive:
The next step requires a lot of files by name, so the File System is initialized, and the Boot Drive is Mounted. If the drive directory is damaged, the drive can not be Mounted, so your Mac begins one pass of Disk Utility Repair. This will take an additional about five minutes. During this process, the progress bar may be extended, and will grow by an additional amount not seen on a routine startup.
at the end of that process (which should not take more than about five minutes), it will attempt to Mount the drive again:
-- if the drive Mounts, boot-up continues.
-- if the drive cannot be Mounted, your Mac can do nothing more, so it powers off.
-- if the process stalls, this may indicate you have Bad Blocks on your Rotating Magnetic Boot drive (if so equipped). The re-reading of Bad blocks can take a very long time (on the order of a quarter minute for each Bad Block).
The initial "chime" sound is generated in software when your Mac passes the Power-On Self Test. If it occurs and/or startup continues, your Mac is working. The blank gray screen should light up. If the picture is distorted, you may have a graphics card problem as well. Then on to the disk Drive.
Accessing the Boot drive:
The solid Apple is not in the Mac's ROM at Cold start. The Apple logo can only appear when it is fetched in the first "blob" of software loaded from a 'magic' place on the boot drive, or re-run after a Restart. Then a whole lot of stuff is initialized, and the progress Bar moves part way across. After a cold start, seeing the solid Apple appear says your drive is not completely dead.
Mounting the Boot drive:
The next step requires a lot of files by name, so the File System is initialized, and the Boot Drive is Mounted. If the drive directory is damaged, the drive can not be Mounted, so your Mac begins one pass of Disk Utility Repair. This will take an additional about five minutes. During this process, the progress bar may be extended, and will grow by an additional amount not seen on a routine startup.
at the end of that process (which should not take more than about five minutes), it will attempt to Mount the drive again:
-- if the drive Mounts, boot-up continues.
-- if the drive cannot be Mounted, your Mac can do nothing more, so it powers off.
-- if the process stalls, this may indicate you have Bad Blocks on your Rotating Magnetic Boot drive (if so equipped). The re-reading of Bad blocks can take a very long time (on the order of a quarter minute for each Bad Block).
Grant Bennet-Alder has some good advice.. i’d also replace the pram battery, which is behind the graphics card; it’s a small button battery and it does die After about five years or so, the exact replacement is a BR - 2032, but A CR-2032 will work. Looks to me like you may have a graphics card problem. You could also try resetting the SMC / PMU and then zapping the PRAM four times on start up after you have replaced the pram battery. A new battery is about $7, and resetting the SMC/PMU And zapping the pram is free. You could try blowing out the dust from the graphics card, Provided that you follow the proper procedures before trying to do so and seeing if that makes a difference. If you reboot your Mac pro and hold down the D key on your keyboard, You should get apple diagnostics which will run some Basic tests. If your GPU has gone bad you’ll have to replace it luckily this is not difficult.
john b
2008 mac pro not booting
