While investigating the source of my 3x iMac slowdown, I learned that in order to keep the system running optimally, Mac OS X has to perform periodic system maintenance . This maintenance is scheduled to run automatically from 3:15 am to 5:30 am.
However, if your computer is off or in sleep mode at night, the maintenance tasks won't run. Mac OS X does not warn the user if system maintenance hasn't been run in a while; unfortunately, OS X does not re-schedule the tasks to run at other times.
Ironically, MAC OS X ships from the factory with sleep mode turned on, so by default, the maintenance tasks are not run.
Here is how you can force maintenance to run:
- Open Terminal (/Applications/Utilities).
- Type: sudo periodic daily (or "weekly", "monthly")
- Press Return.
- Enter your Admin password when prompted, then press Return.
- Quit Terminal when the task is complete
Not very Mac friendly...
Alternatively, you can use a shareware program called macaroni to perform regular system maintenance on Macs that are off at night.