Updated my version of emClient to the most recent build 7.2.33870.0 and all of a sudden all my Gmail folders are getting back 
slashes in front of them?
Also I did notice that after upgrading the software needed to run through Authorisation to connect to gmail again despite the fact I’d been using it for years from the first time I added the account.
What happens if you remove the GMail account from eM Client, then add it again?
I already tried that. Its now settled in and I’ve been using it and ignoring it for a week but Inbox, Sent and Draft all have the \ in front of them now. Would like to fix it and I’m 99% sure it happened when the upgrade to the most recent version was done.
I am not a GMail user, so some of the issues with that provider are beyond my experience.
One thing you can try is to rename the database, then start with a fresh empty one and see if there is any difference. To do that close eM Client then rename the C:\Users_username_\AppData\Roaming\eM Client\ directory. You may have to enable hidden items in Explorer to do that.
When you restart eM Client, it will go through the setup of a new account. See if that solves the issue.
Another option is to uninstall eM Client, the download and install the previous working version from http://www.emclient.com/release-history