9 Replies Latest reply: Mar 30, 2014 10:38 AM by BDAqua
pearldivers Level 1 (5 points)

Last two days I'm getting the prohibition symbol when I try to start up

my G4.


After several minutes, a blue screen appears...then another longish wait...

then my computer starts up. At least something!


I then get "The disk you inserted was unreadable on this computer",

but there's nothing in the combo drive.


The machine then functions normally, but I get the same issue

each time I shut down and then attempt to re-start.


I've disconnected all peripherals, same result.


I can't boot cleanly from the installation disk (C key)...I still get all of the above.

I can't boot from my Disk Warrior utility CD either...it starts but then

dies early in its reconstruction process, leaving me with a black

and very dead screen and no further result.


Two years ago I cloned the original start-up disk and have been using

the clone as my start-up ever since. However, the icon for that

original start-up disk has now vanished from the desktop and although Disk

Utility sees it, all the repair and verification boxes are ghosted out,

so I can't do anything with it.


So...is it that original drive that's screwing things, or the clone,

or the combo drive?


Any tips would be appreciated.



Mac OS X (10.4.11)
  • BDAqua Level 10 (122,227 points)



    Can't tell, but it sems some Disk is having a problem, noy likely the  Oprical at this point.

  • rccharles Level 5 (7,574 points)

    Could be the internal hd is going bad.  Remove it.


    How does apple spell a cd/dvd disc or disk?  Some people use disc to refer to cd/dvds.  Disk to refer to hds.

  • pearldivers Level 1 (5 points)

    I re-cloned the cloned ATA drive to a new SATA drive,

    and the G4 now starts up perfectly.


    That ATA clone takes a few minutes to appear on the

    desktop, and often Disk Utility cannot locate it until

    after quite a long time of searching.


    But I'm still getting the "Disk unreadable" warning after

    start-up from the new SATA drive.


    Sounds like I need to replace/remove the "disappeared" ATA

    as well as the original cloned ATA drives.(??)


    Will do so today, but meantime at least the machine

    is working normally at start-up.

  • rccharles Level 5 (7,574 points)

    But I'm still getting the "Disk unreadable" warning after

    start-up from the new SATA drive.


    Mac OS X tries to mount all local disk on the desktop.  X is finding a problem with your old disk ( mostlikely ).

  • pearldivers Level 1 (5 points)

    It was the start-up disk. I sourced a pair of NOS ATAs

    and whacked them in. Everything is fine now.


    Incidentally, the two original ATAs I bought on the

    same day from the same vendor. Exactly two years

    ago this month. One was WD, the other Seagate (the last two the dealer had).

    They both failed just 48 hours apart from each other!


    Thanks to other posters for their tips.



  • BDAqua Level 10 (122,227 points)

    Great hear, good work Jet, thanks for yhe report!

  • pearldivers Level 1 (5 points)

    Hmmm. The plot thickens.


    New SATA drive just failed. Icon gone from desktop,

    Utility can't find it.


    That's three failed drives in 5 days...

  • rccharles Level 5 (7,574 points)

    Maybe it's not a drive failure, but some other common component like disk controller.



  • BDAqua Level 10 (122,227 points)

    Yeah, that's what I'm wondering, I was thinkong possibly RAM messing the drive up good, or maybe PSU?