Trying to fix an issue on my fathers computer.

He's using Windows Live Mail to host his email account from the ISP (eg: *** Email address is removed for privacy ***). Personally I hate these email accounts and want him to move to a Gmail or Outlook online email account, but he wants to stick with this... Anyway, for some reason recently it keeps downloading thousands of his old emails that he's deleted. I've found other forums posts saying to right click on the Inbox or other folders, go to Properties, Synchronizing tab, then change it so that it only synchronizes new emails.

When I get him to right click on the inbox or others, and then going into Properties, this properties window only has a General tab that lets you rename the folder.

Any ideas how I can fix this? Are there other ways to change this setting.