It sounds like your Mac is set to automatically log you out after a period of inactivity. Open System Preferences from the Apple menu in the top-left corner. Open the “Security & Privacy” preference pane.

How do I stop apps closing on my Mac?

What to do when your Mac apps crash or freeze? Fix 1. Force quit the app. Fix 2. Restart or update the app on Mac. Check and apply software updates. Fix 3. Check app compatibility. Fix 4. Delete preference file. Fix 5. Delete cache.

Do programs still run in sleep mode Mac?

When the display is sleeping but the computer is not, programs on your computer continue to run normally. When your Mac enters computer sleep, programs are paused, and will resume when the computer is awakened (but some programs, especially those that rely on network communications, can’t resume seamlessly).