Are you planning to upgrade to Configuration Manager Current Branch 1810 and actively using the Upgrade Readiness integration feature? Then this blog post might save you some headaches (and flooded inboxes) later on.
Shortly after upgrading to Configuration Manager Current Branch 1810 last week, a customer reported the volume on the site server rapidly filling up. Further research indicated a large amount of files were dropped in one of the inboxes: %ProgramFiles%\Microsoft Configuration Manager\inboxes\hman.box\CFD
Looking into these files further pointed to a potential issue with the Upgrade Readiness integration, which was enabled in this particular environment.
The dmpdownloader.log indicates the Upgrade Analytics download interval is set to 0 and running continuously.
In the meantime Microsoft has published KB4498259 confirming this is a known issue with Current Branch 1810. The fix comes with the 1902 release and in the meantime a workaround is to (continuously) set the download interval in the registry.
More details in the KB article here.
Hope it helps.
Tim
