Keep in mind for iMessage, cache is your message history, so you may lose your chats across all devices. If iMessages not working on Mac is troublesome, it’s possible you just need to clear your cache. All you need to do is log in when you see the boot screen after the restart.
Sometimes, a good 'ol reboot fixes everything. One of the more common issues with iMessage is a message not sending on Mac or iMessage not delivered on Mac, even when chats are popping up elsewhere. If iMessage on Mac not working is something that is dogging you, give these fixes a shot: Reboot Mac Still, it's worth troubleshooting, as one of the solutions below likely solves any iMessage woes. Because each Mac has different settings and unique app settings, there's not a single answer that works for everyone. Why won't iMessage work on my Mac? It's a simple question with several possible solutions. Try free How to fix iMessage not working on Mac