Your hard drive begins to chatter at a level that could compete with roomful of agitated chimpanzees. Technically, it's called "excessive disk activity." At the same time, the responsiveness of your Mac drops to near zero. Activities that should take no more than a second, such as dropping down a menu, take a few minutes.
What's happening? Most likely, some software process is hogging your Mac's CPU with the result that your Mac has almost no energy left to do anything else. This is not a new bug. However, it continues to be one that bugs me on a regular basis, especially on my aging Power Mac G5.
If this happens to you, the simplest remedy is to restart your Mac. However, if you'd prefer to avoid the wasted time and irritation involved with a restart, there are alternatives.
For starters, launch Activity Monitor (assuming that your Mac is still capable of successfully launching an application in a reasonable time). Check out the CPU column. Most likely, one process will show an alarmingly high CPU percentage (often in excess of 70 percent). That's your culprit.
You could select to Force Quit the process from Activity Monitor. That might work. But, depending on the process, it could lead to other undesirable symptoms.
Happily, there are more specific and safer solutions. I'm going to describe two of them; the first one today and the second one next week.
If Activity Monitor cites SyncServer as the CPU hog, a solution is to "reset the SyncServices folder" (located in ~/Library/Application Support).
Wait! Don't simply delete the folder. In a rare show of tech support humor, Apple advises staying away from the folder "as if it were a swarm of bees." Instead, to perform a reset, follow the procedures in this Apple KnowledgeBase article. Note that the article does not cite CPU overload as a potential symptom. However, numerous reports on the Web (as well as my own experience) confirm that it is.
The article offers two possible fixes. The first is to go to iSync's Preferences and select Reset Sync History. If that doesn't work (and it probably won't), the second and overall preferred solution is to run a hidden Terminal command. To do so, launch Terminal and type:
To make it easier to run this command on future occasions, navigate in the Finder to the Resources folder where the command is buried. From here, make a copy of the resetsync.pl file and place it on your Desktop (or any other convenient location). The next time you want to run the command, launch Terminal and drag the copied resetsync.pl file to the Terminal window. The command will appear after the prompt. Just add full to the end of the line and press Return.
A minor downside of doing this reset is that you will next need to reset your MobileMe syncing options. However, this is typically as simple as clicking Sync when you see the message shown above. If your synced data are current on all your devices, it shouldn't matter which action you select from the pop-up menu. If in doubt, leave it at the default choice: "Merge all data."
This story, "Bugs & Fixes: Dealing With CPU Overloads, Part One" was originally published by Macworld.