MacOS – Mac wakes up from sleep every two hours on Mac OS X Yosemite

Since upgrading to the first stable release of Mac OS X Yosemite a few days ago, my Mac Mini wakes up roughly every two hours from sleep for about a minute, then goes back to sleep. This is particularly annoying at night since I sleep my Mac, and it's in the bedroom, so I notice when it turns on.

In my Console, here's some of the lines from it from when it wakes up:

14/10/19 6:48:06.000 am kernel[0]: Wake reason: RTC (Alarm)
14/10/19 6:48:06.000 am kernel[0]: RTC: Maintenance 2014/10/19 10:48:06, sleep 2014/10/19 09:00:12
14/10/19 6:48:06.001 am SyncServer[910]: [0x7fdd69c19d80] |SyncServer|Warning| Refreshing watchdog because of a calendar time change alert.
14/10/19 6:48:06.000 am kernel[0]: Previous sleep cause: 5
14/10/19 6:48:06.000 am kernel[0]: AppleThunderboltNHIType2::prePCIWake - power up complete - took 1 us
14/10/19 6:48:06.000 am kernel[0]: The USB device USB 3.0 HUB (Port 1 of Hub at 0x15000000) may have caused a wake by issuing a remote wakeup (1)

From the last line, yes, I've got a USB 3 hub plugged in to my USB 3 port on the Mac. But there are no devices plugged into the hub. Nevertheless, I'll try unplugging it tonight, but I suspect it won't make a difference.

Also, I've already disabled "Wake from network access", disabled "Power Nap", and pretty much disabled everything else in the "Energy Saver" system preferences pane.

When I run pmset -g, I get:

Active Profiles:
AC Power    -1*
Currently in use:
 standby              1
 Sleep On Power Button 1
 womp                 0
 autorestart          0
 hibernatefile        /var/vm/sleepimage
 darkwakes            0
 networkoversleep     0
 disksleep            0
 sleep                0 (sleep prevented by iMovie, coreaudiod, iTunes, AddressBookSour)
 autopoweroffdelay    14400
 hibernatemode        0
 autopoweroff         1
 ttyskeepawake        1
 displaysleep         60
 standbydelay         4200

I often have wake problems with my Mac, especially after upgrading to a new OS, and this time is no exception:

1. OS X Mavericks wakes my Mac from sleep every hour or so
2. Mac wakes up from sleep every night and then goes back to sleep immediately