My computer accepts sleep function and blacks out but after 30minutes or so wakes up again, without prompting, to a bright blue screen (without screen saver). I have rebooted and switched off completely but this has made no difference to the problem.
iMac 21.5" 4K, macOS 10.14
It's probably turning on because you have enabled Power Nap and Wake for network access. Try disabling both to see if that helps. If your iMac has an SSD then disable Put hard disks to sleep. If the HDD is put to sleep along with the computer, then there is a long delay when waked up because it takes the HDD time to spin up.
It's probably turning on because you have enabled Power Nap and Wake for network access. Try disabling both to see if that helps. If your iMac has an SSD then disable Put hard disks to sleep. If the HDD is put to sleep along with the computer, then there is a long delay when waked up because it takes the HDD time to spin up.
You can save us asking dozens of questions by submitting a report...
EtreCheck is a simple little app to display the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to help people help you with your Mac.
http://www.etresoft.com/etrecheck
Pastebin is a good place to paste the whole report if you capture the URL while there…
Workable but harder for me to work with...the Note tool on the bottom of this editor's toolbar, as shown in the image, to copy and paste the output from EtreCheck. In a Reply before you click post, look for this to add longer texts...
Kappy, thank you for the helpful advice. I have disabled the two functions you suggested and the problem seems to have been fixed - at least for the past 48 hours or so the computer has kept asleep when ordered to!
I am also having the same problem. What is causing the bright blue light? It stays on continuously until I 'wake' the screen again - can be up to 12 hours on. Is this related to the Energy Saver preference mentioned above?
Check your Energy Saver preferences. Which options do you have checked?
Preferences checked are:
Put hard discs to sleep
Wake for network access
enable power nap
Where are you seeing this blue light?
Sleep function on my iMac
