Diagnostics

AppleJack 1.5 Donationware (universal) Troubleshooting/repair utility.
http://sourceforge.net/projects/applejack
REQUIREMENTS PowerPC Mac OS X 10.4 & 10.5 NOT COMPATIBLE WITH SNOW LEOPARD WAiT!
AppleJack is a user friendly troubleshooting assistant for Mac OS X. With AppleJack you can troubleshoot a computer even if you can't load the GUI, or don't have a startup CD handy. AppleJack runs in Single User Mode and is menu-based for ease of use. Using AppleJack, you can repair your disk, repair permissions, validate the system's preference files, and get rid of possibly corrupted cache files. In most cases, these operations can help get your machine back on track. The important thing is that you don't need another startup disk with you. All you need to do is more...restart in Single User Mode (SUM), by holding down the command and s keys at startup, and then typing applejack, or applejack auto (which will run through all the tasks automatically), or applejack auto restart (which will also restart the computer automatically at the end of the process). WHAT'S NEW * Leopard compatibility! (Thanks Steve Anthony!)

AppleJack 1.4.3 Donationware (universal) Troubleshooting/repair utility
http://sourceforge.net/projects/applejack
REQUIREMENTS PowerPC Mac OS X 10.2 or later. Use this version for Jaguar and Panther Systems. I still use this one with Tiger.
AppleJack is a user friendly troubleshooting assistant for Mac OS X. With AppleJack you can troubleshoot a computer even if you can't load the GUI, or don't have a startup CD handy. AppleJack runs in Single User Mode and is menu-based for ease of use. Using AppleJack, you can repair your disk, repair permissions, validate the system's preference files, and get rid of possibly corrupted cache files. In most cases, these operations can help get your machine back on track. The important thing is that you don't need another startup disk with you. All you need to do is more...restart in Single User Mode (SUM), by holding down the command and s keys at startup, and then typing applejack, or applejack auto (which will run through all the tasks automatically), or applejack auto restart (which will also restart the computer automatically at the end of the process). Compatible with Intel-based Mac OS X systems.

Caffeine 1.1.1- Universal Freeware Menubar item prevents your Mac from sleeping and more.
http://lightheadsw.com/caffeine/
Requirements: Mac OS X 10.5 or later. Works with Snow Leopard. Earlier 10.4 1.04 version on disk.
Caffeine is a tiny program that puts an icon in the right side of your menu bar. Click it to prevent your Mac from automatically going to sleep, dimming the screen or starting screen savers. Click it again to go back. Hold down the Command key while clicking to show the menu.

CalibrationAider 1.1 Universal Freeware Realize the full potential of a computer display device.
http://www.imagingassociates.com.au/color/software/calibrationaider.jspx
REQUIREMENTS Java Runtime Environment (JRE) version 1.4.2 or later.
Realize the full potential of a computer display device. CalibrationAider helps you realize the full potential of your computer display device. Use CalibrationAider to create a consistant, reproduceable viewing environment with an optimal viewing angle, screen resolution, and maximized range of colors. CalibrationAider displays built-in test-patterns and allows you to import your own images. CalibrationAider includes a complete user guide and tutorial that describes how to use test-patterns to calibrate your LCD or CRT monitor and introduces concepts important to digital image processing and color management in general. CalibrationAIder is ideal for digital photographers who need to set up a color-managed workflow, or home users who want to more...display digital photos to best effect. It is also useful to carry a copy on CalibrationAider on a USB Flashdrive so it is at hand to test that expensive new LCD Monitor before purchase! CalibrationAider runs on any operating system with a Java Runtime Environment of version 1.4.2 or newer installed. The latest version of Java is available from http://www.java.com/.

Check Failed Password Attempts 0.1.9 Freeware Displays /var/log/secure.log file.
http://www.jonn8.com/html/FailedPWAttempts.html
REQUIREMENTS Mac OS X 10.2 or later, Admin access.
Check Failed Password Attempts is a small application that parses the /var/log/secure.log file looking for failed authorization attempts. It presents a summary of the total number of failed attempts (and successes) per user. It will also optionally display the full log listing of each failed attempt, each successful attempt, and SSH information from the /var/log/system.log (see the preferences to enable/disable these options). 

Drive Monitor 4.1 Freeware - Determine used/unused space on mounted volumes.
REQUIREMENTS Mac OS 8.6 or later, including OSX
Determine used/unused space on mounted volumes. Drive Monitor displays information about volumes mounted to your computer, including which volumes are currently mounted, and how much space is being used on each of them. The main window shows the name and icon of each volume as well as their size, used space, free space, percent used, percent free and a "thermometer" graphic representation. It is possible to sort the display by any of these items. If a volume is locked, a padlock icon is shown to the left of the drive name. Nearly-full volumes are hilighted in a used selectable color at a user-specified threshold. The more...bottom of the window provides a summary of all of the drives shown.  4.1 adds a few bug fixes and native OS X support.

FixDate for OSX 1.6 Freeware
http://www.xeromag.com/fvshare.html classic version available on website
REQUIREMENTS Mac OS X 
FixDates is a simple, fast program designed to search through a folder looking for files with invalid creation or modification dates (such as January 1, 1904). If it finds such files, it sets the creation and/or modification date to the current date. Macintosh only.  

GeekTool 3.0  Freeware Display log files, UNIX command output, and more.
http://projects.tynsoe.org/en/geektool/
REQUIREMENTS Mac OS 10.5.7 or later. earlier version of disk for Mac OS X 10.3.9 or later.
GeekTool is a PrefPane (System Preferences module) for Mac OS 10.5. It let you display on your desktop different kind of informations, provided 3 default plugins :
File plugin to monitor MacOS X activity with /var/log/system.log, or any file that you want to follow.Shell mode to launch custom scripts or commands like "df" to check space left on filesystems, "uptime" to monitor load of your machine... Finally, Image mode helps you monitor bandwith usage, CPU loads, memory availability of your server, via tools like MRTG or RRD.
GigaMeter 1.01  Freeware
REQUIREMENTS Mac OS X 
Modifies kext file to allow processor identification and speeds. Good for aftermarket processors.

Grackle Probe X 1.4 Freeware Enable Quartz Extreme for AGP & PCI-based Macs.
http://www.stg.com/employees/sbytnar/projects/grackleprobe/index.html
REQUIREMENTS: Mac OS X 10.2 or later, one of the follow Mac models: PowerMac G3 (Beige), PowerMac G3 (Blue & White), iMac G3 233MHz -> 333MHz, PowerBook G3 Series (Wallstreet?), Apr 1998, PowerBook G3 Series (Lombard?), Apr 1999, possibly other older G3 PowerMacs or PowerBooks.
Grackle Probe accelerates Grackle based Macs that are using the Quartz Extreme PCI hack that's been mentioned recently. Grackle Probe could accelerate Grackle based Macs that have high-performance PCI cards, without needing to use the Quartz Extreme PCI hack or any undesirable side effects that QE has. It is not known what the compatibility or the side effects of enabling PCI Store Gathering is.

GrandPerspective 1.3.3 Freeware Graphically shows disk usage within a file system.
http://grandperspectiv.sourceforge.net/
REQUIREMENTS: Mac OS 10.3 or later
GrandPerspective is a small utility application for Mac OS X that graphically shows the disk usage within a file system. It can help you to manage your disk, as you can easily spot which files and folders take up the most space. It uses a so-called tree map for visualisation. Each file is shown as a rectangle with an area proportional to the file's size. Files in the same folder appear together, but their placement is otherwise arbitrary. Use this program for an overview and Whatsize (in this category) to narrow down your search.

Hardware Monitor 4.9 shareware $10 (Lite free) Hardware monitoring sensor app.
http://www.bresink.com/osx/HardwareMonitor.html
REQUIREMENTS Mac OS X 10.4 or later. 
Hardware Monitor is an application to read out all available hardware sensors in Macintosh computers. The program can display and visualize measured values in a large variety of fashions. It can also store and export readings. The application Temperature Monitor is available for free, but is limited to accessing temperature sensors only.

HighLoad 1.9.8 Freeware Pushes your computer to the max to help diagnose problems.
REQUIREMENTS Mac OS X 10.3 or later. Leopard tested
HighLoad is a tool which will push your computer to the max to help diagnose most intermittent problems. This tool meant for time testing a machine. The application will not diagnose the machine for you, you must gather info from the log files and develop a conclusion. HighLoad can also run routine tasks such as rebuilding the Spotlight index files, and clearing System Cache files to make sure your computer is running at its best.

iBatt 2.0 shareware $19 Advanced PowerBook battery monitor.
ty@raynersoftware.com, http://www.raynersoftware.com/ibatt/
Requirements: PowerBook or iBook, Mac OS 10.4 or later
iBatt is an advanced PowerBook battery monitoring and diagnostic program. iBatt gets information about your battery that the system doesn't tell you, such as its total capacity, voltage output, and rate of charge/discharge.

InsomniaX 1.3.5 freeware (universal) Disable sleep mode on an Apple Laptop.
http://semaja2.net/insomniaxinfo
Requirements: PowerBook or iBook, Mac OS 10.4 or later Snow Leopard Tested
InsomniaX disables the sleep mode on a Apple Laptop allowing you to play music through speakers while it's closed. Also adds the option to enable hibernation mode.

iRepair 1.0.6 Freeware (universal) Corrects ownership and permission of your files and folders.
http://www.stereo2software.com/
Requirements: PowerBook or iBook, Mac OS 10.3.9 or later. Leopard Ready
iRepair correct ownership and permission of your files and folders. This tool takes advantage of Apple's Security Framework and Universal Binary.

Jiggler 1.4 freeware (universal)  - Prevent screensaver and screen mode activation.
Stick Software, http://www.sticksoftware.com
Requirements: Mac OS X 10.3 or later
Jiggler keeps your Mac awake through those lengthy tasks when it would rather fall asleep, by jiggling your mouse periodically.

LCDTest 2.0 freeware LCD display tester.
REQUIREMENTS Mac OS X 10.1 or later, LCD display
LCD display tester. LCDTest is a small application to assist in common LCD adjustment tasks by providing test patterns. These tasks include: Adjusting analog LCDs, ,Detecting dead/lazy pixels, Checking for panel alignment, Checking color transitions. These test patterns are designed to work for both monitors and projectors in single or multi-display configurations. To test the desired display device, drag the 'LCDTest' window onto the display you wish to test. Then click the 'Show Pattern' button. All test patterns are terminated with a mouse click or by pressing the ESC key.

Mac HelpMate 3.0 freeware  - System repair, info, diagnostics & tweaks.
Turingart, sales@turingart.com, http://www.turingart.com/
Requirements: Mac OS X 10.3 or later, BSD Subsystem Snow Leopard Tested
If you're a Mac support professional or consultant, you need this application in your arsenal of troubleshooting tools. It can replace a whole bunch of expensive products, including Timbuktu, eCare, and many others... Mac HelpMate contains powerful diagnostic features, such as the ability to run SMART (S.M.A.R.T) tests, check temperature and hardware sensors, inspected installed packages, repair permissions, clean caches, remove unecessary trash files, ASR multicast server, support for Growl notifications and much much more. 

Mactracker 5.2 freeware  - Database of all Mac models.
http://www.mactracker.ca/
Requirements: Mac OS X 10.4 or later
This app lets you look up your Mac and check what expansion options you have. Mactracker provides detailed information on every Apple Macintosh computer ever made, including items such as processor speed, memory, optical drives, graphic cards, supported Mac OS versions, and expansion options. Also included is information on Apple mice, keyboards, displays, printers, scanners, digital cameras, iPod, Apple TV, iPhone, Wi-Fi Cards and Base Stations, Newton, and Mac OS versions.

Pacifist 2.6.4 Shareware $20 (universal) Install individual files from .pkg installers and more.
CharlesSoft, csrstka@mac.com, http://homepage.mac.com/csrstka
REQUIREMENTS Mac OS X 10.3.9 or later 
Pacifist is a small program that opens up .pkg installer packages and lets you install individual files out of them. This is useful if you need to install just one file out of a package instead of the entire package (for example, if you deleted your Preview application and need to reinstall it, but not the whole operating system), if you experience bugs in Installer.app that mess up your symbolic links, or if you just like a little more control over the installation process. 

PlistChecker 1.5.1 freeware  Displays report listing any plist problems found.
http://www.jwwalker.com/pages/plistchecker.html
Requires: Mac OS 9.0 or later.
PListChecker — After spending too many hours wondering why my document icons weren't showing up under Mac OS X, and finally figuring out that it was caused by a typo in my 'plst' resource, I wrote this utility to help other Mac OS X programmers. Drag a packaged application, or a single-fork application containing a 'plst' resource, or an Info.plist file and drop it on PlistChecker. PlistChecker displays a report listing any problems it found.

Power Fractal 1.4.1 freeware Parallel graphics benchmark app (was AltiVec Fractal).
http://daugerresearch.com/fractals/powerfractal.shtml
(UNIVERSAL) REQUIREMENTS Mac OS X 10.4 or later
WAS: Altivec Fractal Carbon, Power Fractal is a numerically-intensive parallel graphics application that computes a Mandelbrot-like fractal and displays processor performance statistics. This app uses the AltiVec, SSE, and multiple processors (MP) for its computations and uses UCLA AppleSeed's MacMPI library for communication between parallel processors. To run it on a Mac cluster, use Pooch. This code will also compute correctly on single processor machines and non-G4's. Universal Application release for mixed clusters of PowerPC G3s, G4s, G5s and Intel Cores simultaneously. Reoptimized vector algorithms to use SSE on Intel. Endian conversions implemented for communication using MacMPI_XUB.

PreferenceCleaner 1.0.4 Freeware Simplifies the task of deleting preference files..
http://www.echomist.co.uk/software/PreferenceCleaner.shtml
REQUIREMENTS: Mac OS 10.4.4 or later
PreferenceCleaner... Preference files can become corrupt and cause an application to become unstable. Alternatively, if an application has a large array of preferences you might find it simpler to delete the files than to locate a setting which has enabled an undesired behaviour. PreferenceCleaner is a utility which aims to simplify the task of deleting preference files. PreferenceCleaner allows you create and store batch lists of files to be deleted in the event that you need to remove the same files repeatedly.

PrefCheck 3.0 - Freeware Universal Check your .plist files for corruption.
REQUIREMENTS: Mac OS 10.3 or later
PrefCheck is a utility to check your preference (.plist) files at the User and Root Levels. PrefCheck then displays the results of EVERY file checked in your default Text Editor. It also has the ability to turn off the Crash Submission window or automatically take you to the Crash Submisison Form.

Preferential Treatment 1.1.8 freeware (universal) Scans for corrupt preference files.
Jonathan Nathan, bemailer@aol.com, http://homepage.mac.com/jonn8/as/
Requirements: Mac OS 10.2 or later Leopard Tested
This app checks your preference files (both in your user’s preference folder and the system’s preference folder) for corruption by using the plutil command-line tool. If it finds suspect files, it will list the files and allow you to reveal them in the Finder or move them to the Trash. You may also double-click on a file in the found files table to open it in the application of your choice (you can designate the default application from the preferences). There is also an option to save the results of a scan to a text file. (Note: if you trash a file before saving a report, the report will not include information on the file you moved to the Trash.)

Quartz Extreme Check 1.2—Freeware Checks if Quartz Extreme acceleration is active.
http://www.entropy.ch/software/macosx/#quartzextremecheck
Requirements: Mac OS 10.2 or later
Confirms that Quartz Extreme is enabled on your system. Frequently used to verify that your modification when adding a PCI based graphics card is properly working.

ReDiscMove 1.0—Freeware Forces a disc in your CD/DVD drive to eject.
Requirements: Mac OS 10.4 or later
ReDiscMove forces a disc in your CD/DVD drive to eject. Very useful when you accidentally put in a disc with an autostarting windows software.

SlimBatteryMonitor 1.5 Freeware but accepts donations Space efficient battery/UPS power menu item.
http://www.orange-carb.org/SBM/
REQUIREMENTS Mac OS X 10.5 or later. Snow Leopard Tested. 1.4 Tiger version on disk
Space efficient battery/UPS power menu item. SlimBatteryMonitor is a space-efficient replacement power gauge for your Mac OS X menu bar. It monitors both laptop batteries and many UPS batteries. You can select different views for when powered, charging or on battery... even instruct SlimBatteryMonitor to automatically hide itself in some circumstances (e.g. while fully charged). A graphical icon shows the power remaining, and can be accompanied by a text description (battery charge in percent, or time remaining). Colours indicate whether the system is fully charged, charging or on battery. In some cases, SlimBatteryMonitor can be 70% slimmer than Apple's system meter... With SlimBatteryMonitor you'll have more...room for other important menu bar items. Version 1.4: Universal binary supports both PowerPC and Intel-based macs.

Smart Reporter 2.4.6—Freeware Hard drive pre-failure warning utility.
http://www.corecode.at/smartreporter/
Requirements: Mac OS X 10.5 or later. At least one ATA, SATA or eSATA hard disk drive. Panther/Tiger version on Disk
SMARTReporter is an application that can warn you of ATA hard-drive failures before they actually happen! It does so by periodically polling the S.M.A.R.T.-status of your hard-drives. S.M.A.R.T. (Self-Monitoring Analysis and Reporting Technology) is a technology built into most modern hard-drives that acts as an "early warning system" for pending drive problems. Because SMARTReporter relies on the S.M.A.R.T. implementation of Mac OS X, it only supports ATA or S-ATA hard-drives, if you want S.M.A.R.T. support for your SCSI, USB or FireWire hard-drive, send feedback to Apple. SMARTReporter can notify you of impending drive failures by sending e-mails, displaying a more...warning dialog or executing an application. The current status of your drives is always displayed through the customizable menu item.

SMART Utility 2.2.2—Demo $25 universal  Checks the hardware diagnostics system of hard drives.
http://www.volitans-software.com/smart_utility.php
Requirements: Mac OS X 10.4.11
SMART Utility is an application to scan the internal hardware diagnostics system of hard drives. SMART (Self-Monitoring Analysis and Reporting Technology) is a system built into hard drives by their manufacturers to report on various measurements (called attributes) of a hard drive's operation. The attributes can be used to detect when a hard drive is having mechanical or electrical problems, and can indicate when the hard drive is dying. This allows time to hopefully backup, and then replace the drive. Run this utility once a week or more to ensure your HD, and your data, are okay! NOTE: The demo is runs for 30 days or 15 launches, whichever is longer.

SoundSource 2.5 —Freeware Switch your audio input sources easily.
http://www.rogueamoeba.com/freebies/
Requirements: 10.5 Leopard, 10.6 Snow Leopard 2.4 Tiger version on disk.
SoundSource is a tiny tool for OS X enabling you to switch your audio input and output sources with a single click. And with the System setting, you can transfer system beeps to a secondary audio source so you won't be disturbed.

Speed Run X 1.2 —Freeware Speed benchmarking app.
http://www.danicsoft.com/index.php?content=utilities/speedrun/index.php
Requirements: Mac OS 10.1 or later
To use SpeedRun, all you have to do is click the Run Tests button. SpeedRun will proceed to test the speed of your system, then show you a comparison of your system to other systems. You can choose to save the result or discard it. It is a good idea to run two tests in a row, because the second test is nearly always more accurate. As of version 1.2, you can update the results database by going to the internet menu, then choosing "Update Database". Works in OSX but will also work in OS9.

System Optimizer X 4.7.4 shareware -Panther and below system maintenance tool.
http://www.mkdsoftware.com/socks/
Requires Mac OS X 10.2 to 3.9 
This is the old version I prefer for older OSX systems, for its simplicity.  I prefer it over the upgrade to SOCKS. System Optimizer X is a powerful system maintenance and optimization tool, with a uniquely simple design. System Optimizer X uses built-in system tools, and applies proven system-level tweaks and modifications to improve your system, internet, and disk speed and stability. System Optimizer X's main features include: Update prebindings Run system maintenance scripts Clean system/application cache Repair UNIX file permissions Optimize your internet connection Compress minimized windows to save memory Use the "Optimize" feature to queue Repair file permissions, Update prebindings, Run system maintenance scripts, and Clean system / application cache to run in succession. The convenient schedule feature also lets you schedule tasks to automatically run at custom times at weekly, bi-weekly, monthly or bi-monthly intervals.  What's New In This Version: Addressed incompatibility with Case Sensitive HFS+ volumes. Tweaked assignment of file permissions to cache directories.

Tempurature Monitor 4.9 freeware Displays processor temperature.
http://www.bresink.de/osx/TemperatureMonitor.html
REQUIREMENTS Mac OS X 10.4 or later and a supported machine.
The download includes Temperature Monitor and Temperature Monitor Lite. Temperature Monitor is an application to read out all available temperature sensors in Macintosh computers. The program can display and visualize measured values in a large variety of fashions.

WhatLCD 1.0 Free Utility to get the type and model number of your LCD.
http://www.agasupport.com/AGASupport/WhatLCD.html
REQUIREMENTS: Mac OS 10.4 or later
WhatLCD is a simple utility to get the type and model number of your LCD on a Macintosh.

WhatSize 4.9.5 Demo $12.99  Helps find out what files are taking up all your HD space.
http://www.id-design.com/software/whatsize/index.php
REQUIREMENTS: Mac OS 10.4 or later Snow Leopard tested
WhatSize is a simple tool that allows the user to quickly measure the size in bytes of a given folder and all subfolders and files within it. You would be surprised at to how many useless files might be laying around on your hard disks. The files and folders are automatically sorted by size, with the biggest sizes first.
Xbattery 1.0.1 shareware $15
Jeremy Kezer, jeremy@kezer.net, http://www.kezer.net/shareware/xbattery/
Requirements: Mac OS 10.1 or later
This OS X battery-monitoring utility allows you to view your 'Book's battery level and charging status in a user-configurable Dock icon. It also provides a variety of graphs that detail your 'Book's battery info, such as its overall capacity and voltage level.

Xbench 1.3  Freeware Benchmarking tool for OS X.  	
by: Xbench http://www.xbench.com/
Requires Mac OS X 10.3 or later.  
Xbench was developed in response to the lack of convenient benchmarking tools on Mac OS X. It provides a range of useful tests, and is constantly being improved to offer accurate results that can be compared between different Macintoshes.