Not an issue, replace server with the cloud and remove cache, temporary is fine

Yeah you can't use words like that. Even many people who won't panic at the word "server" don't really understand what it is.

"This message no longer exists in your Inbox. If you close it, you will not be able to open it again."

What's more amazing is that this state actually happens often enough in Outlook that somebody wrote code to detect it, and to create a message box for the user to warn them about it.

every warning or labelling of an issue is because it happened to somebody, and it needed to be prevented.

It's true in the physical world - signs like 'beware of falling pottery' for example. The electronic world is a facsimile of the real world!

"locally", "the cloud"

Is it local if I stay in the same ZIP code?

Even that can still be too far. I lean towards “your computer” and “their computer”

So what? Most users will understand this or at least get the gist. My mum can ask me what it means and then I can tell her. That's a much better outcome than the original message.

Wrong.

This is stupid, and you are stupid to entertain this idiotic notion.

Let's take another example:

"The mobility device can no longer operate. Your destination is no longer available."

This tells me absolutely nothing. It possibly even implies that something very bad has happened to my destination!

"The bus engine has broken down. Your route destination is no longer in service."

Even to someone who doesn't know what a "bus", "engine", or a "route" are, this is an actionable and clear message. If I don't know what those things are, I can quickly figure out what a bus, engine and route are, or pass the message to someone who does understand.

Removing information and replacing it with nonsense does not make an error message better. You don't need to be technical to be able to make sense of a message.