Everything you need to know about Repairing Permissions (and more)

Kudos for that article, Dan. Although I didn't read it thoroughly it seemed well researched and accurate (based on my experience), balancing and correcting some previous misconceptions and misinformation on the matter. Good material for future reference when anyone goes astray.

@Albert:

Re: It's also worth mentioning that when a third party changed a permission at the system level you can be assured it is with Apple's consultation, in the rare circumstances that would be beneficial

Are you saying Palm consulted Apple before releasing the bogus version(s) of the Palm Desktop installer that made a mess of some important permissions (which, as I recall, Repair Disk Permissions wasn't capable of fully fixing).

Re: No one in OS Engineering runs this task. I have never used it and have never had a permissions issue. Trust me

OS Engineering most certainly doesn't install all the same software that customers who've had permissions issues do.

Albert:

As explained in the article, the Repair Disk Permissions function uses the receipt files on the disk being repaired, not on the current boot volume. So if you repair permissions on a drive containing 10.4.7 while booted from an Install disc containing 10.4, this will not result in "incorrect" repairs. It will work just fine.

I would not confuse what you may read in the "Mac Help" with what Apple engineering tells you. Those Help sections are written by regular technical writers, not engineers, usually just paraphrasing what was in the 10.1 and 10.2 Help section, if they think nothing changed they pretty much just carry it over. I wouldn't go as far as to say Apple is advocating this routine based on that.

It's also worth mentioning that when a third party changed a permission at the system level you can be assured it is with Apple's consultation, in the rare circumstances that would be beneficial

No one in OS Engineering runs this task. I have never used it and have never had a permissions issue. Trust me

Pity they didn't mention the additional advise I see on the boards about repairing permissions, for example, on a 10.4.7 vol using a 10.4 disk. That is pure lunacy and could create a problem The Disk doesn't know what 10.4.7 is, so of course it's going to look like it's "repairing" lots of stuff. Bad idea.

The point of Dan's article at Macworld, however, was to explain that: yes, it is pointless as a *regular* maintenance task, as most software/OS problems have nothing to do with permissions issues.

But, there are some specific situations where this procedure *does* have a purpose, such as when a user specifically knows that they have a permissions-related issue, or if an installer app misbehaves. Every HP software installer for their printers that I've dealt with, for example, *reliably* screws up a significant amount of permissions during its process. After installing that software on a MacBook Pro and my wife's G5 iMac I have *reliably* experienced software and startup issues, such as background processes (I unfortunately don't remember their names) going through the CPU usage roof, as well as fans cranking to their absolute loudest upon an installer-prompted restart.

These cases admittedly are few and far between, but the point of Dan's article was to elaborate that repairing permissions isn't *completely* useless; it just shouldn't be used as the first line of defense for *every* problem a user might encounter.

It *is* pointless. If it was genuinely a useful bit of routine maintenance it would be in /etc/periodic/daily