After upgrading to v31.0 from v30.0 or v30.1, you've lost your favourite reports and layouts.
We've resolved this issue in Sage 50 Accounts v31.1 and above. Upgrade now if you aren't using the latest version.
If you're unable to upgrade, follow the workaround below.
C:\Users\<Username>\AppData\Local\Sage\Sage Report Designer\SageLine50v30\Favourites
NOTE: Replace <Username> with the login name for the current Windows user.