This article is from the Viruses and the Mac FAQ, by David Harley D.Harley@icrf.icnet.uk with numerous contributions by others.
Since the initial release of this document, a number of people have
E-mailed me asking for help with a possibly virus-related problem.
While I'll always help if I can, I should point out (1) I'm an
experienced Mac user and an IT support professional, but I don't
claim to be a Mac expert (2) pressure of work and other commitments
and a huge E-mail turnover means that I can't promise a quick or
in-depth response [DH]. Whether you mail direct or post to a
relevant newsgroup, it's helpful if you can supply a few details,
* Which model of Macintosh you're using. It may be useful to know
how much RAM it has, the size of the hard disk, and any peripherals
* Which version of MacOS you're using.
* Which applications you're using, and which version. If you're
using Word, it may be critical to know whether you're using version
6 or later, or an earlier version.
* Which, if any, antivirus packages you use, and what version
number. If you're using NAV, for instance, what version?
* List any error messages or alerts that have appeared.
* List any recent changes in configuration, additional hardware
* List any diagnostic/repair packages you've tried, and the
* List any other steps you've taken towards determining the cause
of the problem and/or trying to fix it, e.g. rebuilding the
desktop, booting without extensions, zapping PRAM etc.
Here are a few steps that it might be appropriate to try if virus
scanning with an up-to-date scanner finds nothing. This section
will be improved when and if I have time.
Rebuilding the desktop is by no means a cure-all, but rarely does
any harm. It may be worth disabling extensions when you do this,
especially if the operation doesn't seem to be completed
To disable extensions, restart the machine with the shift key held
down until you see an Extensions Off message. If you're rebuilding
the desktop, release the shift key and hold down Command (the key
with the Apple outline icon) & Options (alt) until requested to
confirm that you want to rebuild.
Disabling extensions is also a good starting point for tracking
down an extensions conflict. If booting without extensions appears
to bypass the problem, try removing extensions with Extensions
Manager (System 7.5) - remove one at a time, and replace it before
removing the next one and booting with that one removed. Remember
that if removing one stops the problem, it's still worth putting it
back and trying all the others to see if you can find one it's
conflicting with. Extensions Manager also lets you disable control
panels. If you don't have Extensions Manager, try Now Utilities or
Parameter RAM (PRAM) contains system information, notably the
settings for a number of system control panels. 'Zapping' PRAM
returns possibly corrupt PRAM data to default values. A likely
symptom of corrupted PRAM is a problem with date and time (but
could be a symptom of a corrupted system file). With system 7, hold
down Command-Option-P-R at bootup until the Mac beeps and restarts.
You may have restore changes to some control panels before your
system works properly. If the reset values aren't retained, the
battery may need replacing.