Messages causing significant battery drain and CPU usage

Hi there ShadowDust99,

We know it’s important to have all the components on your Mac responding, and working as you’d expect. We’re happy to assist and provide guidance.

Do you use Messages in iCloud? Your messages including photos and videos you send and receive are stored in iCloud. If you open one of the conversations, do you see the videos and photos from the conversation? We ask because the attachments may be downloaded from iCloud to your Mac which may cause a large amount of CPU usage.

Let’s also try restarting in safe mode: How to use safe mode on your Mac

Safe mode prevents your Mac from loading certain software as it starts up, including login items, system extensions not required by macOS, completes a basic check of your startup disk, and clears cache. While in safe mode use the Messages app and see if the CPU goes up.

If you have other questions, please let us know.

Take care!

Mine also does this - it's maddening. Since Big Sur update my battery plummets due to this in an hour or less. Nobody seems to know how to fix it.