Gmail not syncing properly

I have started using eM Client today and love it - but upon searching my emails (from Gmail), it seems that the historical messages have not all come across from my Gmail account.

If i search for them in Gmail, I can find them - but not in eM Client.

Could you please advise how to fix this problem?

I have already right clicked on the Inbox and chosen to ‘repair’, but this did not make any difference.

Hello Mathew,
on IMAP accounts, eM Client only downloads the email headers by default, to save time and space on your computer. The full body of the message is downloaded when you open the message and want to read it. This means that searching through all the full messages is not possible unless you have all the messages downloaded.
To download full content of all your messages, go to Tools>Accounts and under the IMAP tab of your gmail account check the option to Download messages for offline use.
Now you will be able to search through all your messages.