Having now upgraded all my Windows 10 machines to the Anniversary Update edition without much in the way of upheaval, I came across the following message on one of them:
Your insider preview build settings need attention. Go to Windows Insider Programme to fix this.
It appeared on the Update screen of the Settings application and I believe that I may have triggered it by letting foolish curiosity take me to the Windows Insider Programme screen. Returning there offered no way of resolving the issue so I had to try the registry editing tip that I discovered elsewhere on the web. Naturally, the creation of a System Restore Point before proceeding with changes to the Windows Registry is advised.
Typing REGEDIT into Cortana brings up a clickable link to the Registry Editor. Having clicked on this, I then clicked on the Yes button on the ensuing dialogue box that Windows 10 throws up every time you make a system change such as installing new software. With the Registry Editor opened, I made my way to the following location:
Once there, I deleted every entry that mentioned “Insider” or “Windows Insider” to leave only two afterwards: “(Default)”, “UnknownErrorDialogValues”. That resolved the issue and I now intend to stay away from the Windows Insider Programme screen in Settings so that the message never appears again.