At around 2:45am every day, some sort of scheduled task is running on my system. Whatever this task is, it is either reading from, or writing to the hard drive, and for several minutes, the system becomes sluggish, with very slow response to clicking on anything, and beachballs. Once the task ends, the system returns to normal. How can I find out what tasks are scheduled to run at different times, on OS X Yosemite? I've tried Googling for the answer to this, but this mainly brings up things about Automator, or other apps that can actually schedule tasks using launchd, etc, rather than listing existing scheduled system tasks. So not really helping. Any help would be greatly appreciated.