I believe I just figured out the issue. For WinServers to auto-launch Plex at boot, in the past we’ve had to install this third-party tool: PmsService (https://github.com/cjmurph/PmsService/releases). It appears this is no longer needed as Plex now has it’s own service built-in and is able to auto launch at boot. I’ve had this tool installed on my Plex servers for years and it never presented a conflict… but I’m guessing it now does with the latest beta build. Now that the feature is integrated, Plex launches it’s own instance of the service at boot and this tool launches a second, eventually leading to the lockout. I don’t believe the tool was needed for Win10, which would explain why @DamnedOne doesn’t have the issue w/ his Win10 machine.
Bottom line, if you have PMServices (PlexService_1.1.2.msi) installed, uninstall it.
Also, I’ve downgraded to Plex-Media-Server-1.9.4.4325-1bf240a65.exe, so unable to provide further logs. Thanks for previous guidance here.
