Disk Warrior alsoft.com
Norton Utilities symantec.com • TechTool Pro/Drive 10 micromat.com

My wax on the Third–Party Disk Utilities is:

• Do Not Let Them "Fix" Anything — except as a last resort.
• Use them only when Apple's FirstAid cannot repair the problem, and for second opinions.
• Leave regular system maintenance to Apple DISK UTILITY, Repair Disk or Disk First Aid.

NORTON Utilities has been discontinued for Mac OS X -- it is know to damage 10.x installs(search GOOGLE for current information). Norton, in particular, is notorious for hosing people's installs, though Norton is one of the most useful tools in my bag. I think the problems most people have with Norton are:

1. They bring Norton in on an already sour disk — and then blame Norton for everything.
2. They run an old version of Norton on a newer Operating System — this is a BIG problem Norton has always had — it literally hoses installs that way.
3. They let Norton "fix" everything.

I never let Norton repair all its crazy bit, date and icon "errors."
I turn off all Norton's bells & whistles.
If Norton does hit a SUSPECT, I always Quit and try to fix it first with Apple's FirstAid.

On the other hand, Micromat's Drive10 utility recovered a lost hard drive — but — the patch took more than half my client's data with it. Further, Drive10 tells me my freshly ZeroWritten hard drives have serious errors!? It is safe to say Drive10 is my LastResort.

In fact, if I have an install that requires a third-party disk utility, I will run the patch, and Erase/Restore the install at my first opportunity.

Norton Tips:

1. Under System 9x, turn off all the Norton extensions except "Norton Shared Lib," i.e., turn off all the bells & whistles.
2. Run Norton AntiVirus on a case–by–case basis by dragging the target icon onto an alias of the Norton AntiVirus application (turn off Auto Protect, unless your workflow requires it).
3. Run Live Update regularly to ensure virus definitions and applications are up to date.

These days I do not even install 3rd–party disk utilities on my working boot system harddrive because I prefer to keep them out of the soup.

I do install Norton Utilities and DiskWarrior on my Maintenance Boot Disk (an external FireWire I use to maintain various Macs). This allows me to attach my FireWire drive to a Mac, boot off my Maintenance Boot System, and run my maintenance and BackUp routines gballard.net.

I've always gotten by with Norton, but I read that DiskWarrior is the utility most preferred by the Mac gurus.