Recently most of the messages from one particular contact in Samsung messenger disappeared. They were not deleted by me and they are not in the trash. The same thing is true when I switch over to Google Messages.
I've restarted my phone and tried to clear the cache in the Samsung messaging app but it is grayed out and I cannot clear it. Restoring from cloud storage produce nothing.
You said most, not all. Are they the ones sent to you or sent by you? If they were sent to you, it is possible the person at the other end "unsent" them. It would be very unusual to lose some parts of a chat and not the whole chat. In order to clear the cache of Samsung messages, you should put it back to your default. You can switch back after if you want to stick with Google. Which messaging app you use has nothing to do with which messages are there or not -- messaging apps are a shell, and if the messages exist on your phone or your carrier's server, they will appear in whichever messaging app you use.
