Display sleeps despite unchecked "Allow Display To Sleep" option on High Sierra
After upgrading to Hight Sierra the display sleeps despite the option "Allow Display To Sleep" being unchecked.
I tried your second tip, but it doesn't work...
You can try a SMC reset to see if that fixes the issue:
Also you can try deleting Amphetamine’s preferences:
• Quit Amphetamine
• Launch Terminal.app (/Applications//Utilities/Terminal.app)
• Type ‘defaults delete com.if.Amphetamine’ without quotes in a Terminal window and press return
• Re-launch Amphetamine
Hope this helps.