It mean its undergoing maintenance... do you not know what that even means? i mean, come on.
Usually it is pre programmed for oil changes and routine maintenance.
Two examples of routine maintenance that should be carried out on your computer
Maintenance Professionals are needed to carry out appropriate routine and non routine maintenance safely so that hardware and software are kept in good condition and up to date.
because it is
non routine maintenance may be needed if you see your system is running slow like a virus scan or if you can tell if something is wrong, then defrag. Non routine maintenance isn't scheduled unline routined maintenance which is done on a regular basis
Several years worth of routine maintenance are executed within a few weeks.
Reset the counters
the number of pages the printer has printed since the last maintenance
This error usually pops up when the PlayStation Network is down for maintenance. Today, on March 9, 2011, the Network will be down for most of the day during routine maintenance.
Your car/van/motorbike
there is something wrong with your computers HTML codes or facebook is undergoing maintenance