Mini-Tutorial: The dreaded spinning pinwheel; Avoiding unresponsiveness/slow-downs in Mac OS X

Patience may be a virtue, but in the case of Mac OS X's dreaded spinning pinwheel process indicator, even the most tranquil users can find themselves more than a tad anxious for the standard arrow cursor to re-appear and normal system operation to appear.

While virtually all users will experience a spinning pinwheel (and associated unresponsiveness from a specific application, a group of applications or the entire system) from time to time, there are a number of measures you can take to lessen the occurrence of these incidents and eliminate standstills.

Add more RAM The primary cause for overall slowness in Mac OS X and unresponsiveness from applications is a lack of adequate memory. For most users, 512 MB is the amount of RAM at which most unresponsiveness and spinning-wheel sessions dissipate. In other words, 384 MB of RAM may leave you in a lurch, while 640 MB of RAM won't provide a huge speed increase over 512 MB.

As an application uses up available RAM, Mac OS X's virtual memory system allocates swap file space on the root file system (your startup disk) for use by the application. With too little physical RAM, this swapping will occur more frequently resulting in two consequences:

• Since all mass storage devices (hard drives, flash memory, etc.) are significantly slower at moving data in and out than physical RAM, applications will suffer a significant speed hit and stall more often.
• Your startup drive will be more occupied with providing virtual memory services to Mac OS X than performing its normal functions (reading/writing files), resulting in slower disk activity and overall lackluster performance. This is also referred to as "disk thrashing."

If you are buying a new Mac, make sure it is equipped with at least 512 MB from the factory, or purchase additional memory modules from a trusted vendor and install them once your system arrives. If you're currently running a Mac OS X system with less than 512 MB of RAM and experiencing frequent slow-downs, consider adding more memory.

Make sure you have enough free space on your startup volume Mac OS X requires at least 10 percent of the volume it is contained on as free space in order to maintain the integrity of the file system. However, even with 10 percent free space, Mac OS X's use swap files - as well as extra data generated by third-party application caches, etc. - can quickly put you back into a position of possible directory/file damage and increased incidence of spinning pinwheels.

Realistically, 20 percent of your Mac OS X startup volume should be kept clear in order to achieve best performance and avoid disk problems.

Delete problematic .plist files Mac OS X uses .plist (preference) files to store various information about applications. Applications routinely interact with their respective .plist files, and when these small dockets become corrupt, individual programs may be more prone to the spinning pinwheel.

If you are having these slow-down issues with a specific application, try deleting its .plist file. It will generally be located in the ~/Library/Preferences folder, and labeled as follows:

com.(name of developer).(name of product).plist [For instance, com.adobe.Reader7.0.plist for Adobe Reader 7.0].

Simply drag the potentially offending .plist file to the trash, re-launch the hampered application, and check for continuation of problems. In some cases, applications will have several .plist files, so make sure you check for any that contain the product name. Also, note that you may lose some settings or other personal data used by specific applications when these files are deleted.

Alternatively, if you're not sure which application is slowing down your Mac or you'd like to check for any existing, but unnoticeable issues, there is a freeware utility called "Preferential Treatment" that will check for some elements of .plist file corruption.

Limiting the number of open applications If you aren't able to purchase additional memory, or if your system continues to experience routine slow-downs despite the presence of adequate RAM, try limiting the number of open applications.

Every open application, even if it is not performing any noticeable tasks, uses a portion of the Mac OS X virtual memory block. Closing unnecessary or infrequently used applications can therefore result in a reduction of spinning-wheel episodes.

More uptime, more stalls: Restart more often Although Mac OS X was designed to run 24 hours a day without a restart and does so well in most cases, some user set-ups may -- for varying reasons -- benefit from more frequent restarts.

Dealing with most notorious culprit: Safari The application implicated in far more spinning-wheel stall instances than any other is Apple's own Safari. Since Safari is tied to so many critical and shared components of Mac OS X -- the WebKit, Java, QuickTime, etc. -- this is somewhat expected. That said, there are a few workarounds that can lessen this behavior.

Disable AutoFill forms A number of user cases have shown that disabling the automatic form filling feature in Safari's preferences can dramatically reduce the number of stalls. In order to do this, open the preferences pane in the "Safari" menu, click on "AutoFill" and de-select all of the available options.

Use keyboard shortcuts instead of mouse clicks For reasons unknown, Safari is sometimes more prone to stalls when mouse clicks are used to perform actions like closing windows or moving to different text boxes on Web forms. Using keyboard shortcuts instead (Command-W to close a window, or the tab key to move between form fields) has been shown to avoid this particular type of problem.

Perform an Archive and Install process As a last resort, performing an Archive and Install process will sometimes eliminate inexplicable stalls that may be due to file corruption.

The process will remove all of your current Mac OS X version's vital (and potentially problem-causing) components, and replace them with the components of a fresh copy provided by the Mac OS X disc that shipped with your system, or a retail Mac OS X disc. Unfortunately, this means you will lose some system settings and some or all third-party system add-ons.

To begin the process, insert your Mac OS X CD or DVD, as indicated above. Restart your machine and hold down the "C" key to boot from the newly inserted disc. Follow the on-screen instructions, and after accepting the license agreement, click "Options." Select "Archive and Install," and check the "Preserve User and Network Settings" option if you'd like to do so.

After the installation process is complete, you will be left with an earlier version of Mac OS X. However, you will likely want to bring your installation back up to the current version of Mac OS X.

Various updates, back through Mac OS X Combo Update 10.2.5, are available from Apple's Support Download page.

Restore your settings and appropriate third-party software, and you will find your system with approximately the same status as prior to the Archive and Install

Your old system will be stored in folder called "Previous Systems" at the root level of your startup volume. If you would later like to delete this folder, you may need to change its permissions.

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