Most emails have disappeared from the folders I have set up

Mail
1

The Emails are still there in the Gmail web GUI though. Is there a way to refresh? Do I need to remove the account from EM Client and re-add?

2

If you right-click on the GMail  All Mail folder in eM Client, and select Properties > Repair, that should force a resync with the server.

3

We have the same problem. We note that this repair button carries a warning. Is there any risk of deleting or moving emails on the google server?

4

The warning refers to local messages, not those on the server. What the repair does is to delete the local message cache, and then download everything again from the server.