Apple recently updated its Knowledge Base guide to troubleshooting software problems. Roll up your sleeves, it's a long list.
Of course, the first item in Mac OS X: How to troubleshoot a software issue is whether the issue is in hardware or software. And that's trouble right away.
Apple suggests that users try fixing software first before thinking about hardware, perhaps because a hardware problem is something that will push users into a support call.
All the same, I advise everyone to check connections of cables first, if there's even the hint that a cable might be pertinent to the problem. And this advice means checking both sides of the connection. It can be very embarrassing.
It is impossible to mount a drive that's not plugged into the host computer you're working from, no matter how many utility programs you run and how long you keep at it. This used to happen with SCSI cables, which often came loose if you didn't screw them in place. Or with RJ-45 Ethernet cables that have the plastic lock broken off.
Shamefaced, I admit that this happened to me the other day. I thought a USB hard drive was plugged into my MacBook Pro, but after checking all the various cables, hubs, switches, drives and I/O wandering around my desktop, I discovered that it wasn't. Wrong cable. Duh!
This can happen with iPods too. The volume on my brand-new iPod nano was way low, even when the control was set to the maximum. I found online a number of tips to fix the problem, including changing the equalization settings in both iTunes and on the iPod, and killing the Sound Check limitations on the iPod. I followed the suggestions and they helped somewhat.
However, the real problem was in hardware — the hard plastic enclosure prevented full insertion of the earphone plug, just by a little bit. It seems that my fancy, sound-isolation buds have a bigger plug head than Apple's standard versions. A few minutes with an x-acto knife and the sound was back to normal.
Reading down the guide, was reminded about problems with cache files. These caches are there to speed up the performance of your application (or browser); each time you open an application, it rewrites the file. But things can go wrong.
If the issue does not appear to be related to preferences, a login item, or a kext file, and persists in Safe Mode, there may be an issue with a cache file in your home folder: Go to ~/Library Drag the Caches folder to the desktop. Attempt to reproduce the issue. If issue is resolved, drag the Caches folder to the Trash. If issue persists, go to /Library. Drag the Caches folder to the desktop. Attempt to reproduce the issue. If issue is resolved, drag the Caches folder to the Trash. If issue persists, go to step 4.
There are several apps that also will hit these caches, including the free (donationware) Cache Out X. It gets at virtual memory swap files, system and user cache files, purges system logs, as well as removing cookies and other Internet related navigation and download cache files.
The current released version of Cache Out X (Version 4.7.2) supports Tiger and late Panther systems. However, in February, developer Christopher Thompson of TriLateral Systems, took over the project and public beta test for a Leopard-compatible version is now available.
It's not advisable to clear these caches out unless you're having a problem. Then again, on an older notebook with limited disk space, this may free up some needed capacity.