Leaving iMac on without sleeping

Nothing bad will happen if you leave it on.

Many users leave their computer on for days or weeks... sometimes months.

Best practice, though, is to reboot the system at least once a week to allow the macOS to do normal housekeeping and disk maintenance chores.

It's all good. 👍🏽

I never put my Mac to sleep I set the display to sleep. Much more efficient and I've been using this practice for over 15 years with no issues. It is wise to restart the computer about 1x week though. Below is a screen shot of my Energy Saver settings

rkaufmann87 wrote:

Nothing happens. It just purrs along good as gold however sometimes mine gets up to go to the bathroom during the middle of the night. :-)

In other words, there is nothing to be concerned about.

I have to do the same. Wow, you must have an old Mac.

Nothing happens. It just purrs along good as gold however sometimes mine gets up to go to the bathroom during the middle of the night. :-)

In other words, there is nothing to be concerned about.

Then your settings are not set correctly. What happens when you restart in Safe Mode, then restart normally and hold down:

Option + Command + Eject keys on the keyboard