My Mac won't go to sleep
If your Mac won’t go to sleep, try this:
pmset -g assertions
Check the output for details on which processes and voodo magic is keeping your iMac up all night:
Listed by owning process:
pid 4627(cloudd)...
Idle sleep preventers: IODisplayWrangler
Things you can try:
- Resetting the printing system (CTRL+click in the left pane of the Printers and scanners settings)
- Unplugging external devices (USB, bluetooth, etc)
- Voodoo
References:
https://discussions.apple.com/thread/7256162
https://www.reddit.com/r/applehelp/comments/43ks7u/macbook_wont_go_to_sleep_hidd_preventing_sleep/