I've a Mac mini (Mid 2010, El Capitan 10.11.6) which acts as file server. I enabled file sharing (SMB).
The Mac goes to sleep mode after 10 minutes (as configured). If a PC client tries to connect to the share (of the Mac mini) it wakes up (as it should). But after the PC is shutdown and there is no user connected to over SMB the Mac mini never goes to sleep mode again. Why?
I've to restart the Mac mini and then it goes again to sleep mode. The Mac mini is connected over an ethernet cable to the network.
Using the following command
pmset -g assertions in terminal before a PC client has connected.
2019-01-05 15:06:26 +0100 Assertion status system-wide: BackgroundTask 0 ApplePushServiceTask 0 UserIsActive 1 PreventUserIdleDisplaySleep 0 PreventSystemSleep 0 ExternalMedia 0 PreventUserIdleSystemSleep 0 NetworkClientActive 0
And after the PC has connected and shut down.