My wifi connection on my iMac shuts down whenever my machine goes into sleep mode. This is inconvenient and seems to interfere in awakening my computer and waiting for the reconnection. This began happening when I installed Sierra and is one of several strange new behaviors triggered by the install. I don't believe my router is the cause b/c all my other devices, phones and iPads continue to operate as usual without interruption. I have run OnyX several times for other issues but this problem continues. Any suggestions to stop this will be appreciated.
Joe
If your Mac is disconnecting from wireless networks upon waking from sleep, try the following steps to resolve the issue. Before beginning, you’ll probably want to be sure you have the appropriate wifi router passwords handy so that you can reconnect to the networks quickly.
1. Go to the Apple menu and choose System Preferences, then go to the “Network” panel
2. Selecting Wi-Fi from the left side menu, click on the “Advanced” button in the corner
3. Click into the “Preferred Networks” box and hit Command+A to Select All, then click the [-] minus button to remove all wi-fi networks – there is no confirmation it just happens instantly.
4. Click “OK” to set that change
5. Back at the Network preference panel, pull down the “Locations” menu and choose “Edit Locations”
6. Click the [+] plus button to add a new network location, give it some name
7. Choose “Done”, then back at the Network panel again join the wi-fi network you want to connect to and enter the login details as usual
8. Choose “Apply” to set the changes and close out of System Preferences
At this point the Mac should have no issue staying connected to the wireless router when woken from sleep, behaving as intended.