TITLE
    Macintosh: Troubleshooting ID=01 "Bus Error"
Article ID:
Created:
Modified: 		8710
9/20/91
9/27/91
TOPIC



    I'm getting a lot of ID=01, "Bus Errors" on my Macintosh.

    It has happened when I'm setting up disks (both floppies and external hard
    disks); it has happened with most of the programs I run; it has happened
    when I try to print. What does it mean?

DISCUSSION


    ID=01, or "Bus Error", is one of the more common System errors, along with
    02, 03, 10, 25, 28. The main reason you are seeing this type of error is
    that the programmers have changed their coding of errors from an ID-XX
    format to a "more helpful" word-based error. A Bus or Coprocessor Error
    can be caused by any application (including the Finder) trying to access
    any memory address in the F hexadecimal range, which accounts for
    approximately 50% of the address ranges in most Macintosh models.

    These errors usually represent some sort of software incompatibility. It
    could be that the application is incompatible with the System version, a
    system extension or INIT (screen dimmer, startup screens, startup sounds,
    etc.) is conflicting with another extension, or the extension is
    incompatible with the System version.

    There are three ways to reduce the frequency of this error:

    1) First try removing all third party extensions (INITs) and control
    panels from your System Folder, as there may be a potential conflict
    there. (If running System 7, holding down the Shift key as the
    Macintosh starts up accomplishes this for the current session.) After
    restarting, if the Bus Error ceases, the problem is with a conflicting
    extension or control panel, or perhaps a combination of them. Move
    these files back into the System Folder gradually, restarting between
    each move, until you identify the conflicting file.

    2) Be sure the computer is free of ANY virus, but particularly the WDEF
    strain. System 6.0.7 has serious problems with WDEF, and in 90% of the
    cases we've seen these bus and coprocessor errors were caused by WDEF.

    3) Throw away the current System Folder and reinstall from known good
    LOCKED disks.

    Use your machine for a day or so before adding extensions or control
    panels back into the system to see if the same errors come up. If they come
    up only in certain applications, check with the software manufacturer to
    make sure you have the most current version, and whether they have seen or
    heard of the problems you are having.

    There is a slight chance the errors are hardware related. If the software
    fixes don't work, try running diagnostics on the hardware. The following
    parts are the likeliest problem spots:

    * RAM
    * Logic board
    * Hard drive



Document Information
Product Area: Computers
Category: Troubleshooting
Sub Category: General Topics

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