I think the OP means that "fsx failed to update" refers to the error message that the installer of the standalone addonmanager displays afterwards. It says something about that "there was a problem updating some of your sceneries.".
That's the reason why I've asked the precise, exact, text of the error.
There are several different messages, some of them are not really a problem (like one of the live update servers momentarily down), other might be a problem and, of course, it's ALSO possible to enable full installation logging, which is always an option to know exactly what's was going on because, even if the installer is "not very clear", it IS logging each and every operation it does, but that is turned off by default, because it wouldn't usually make sense to create a text file with many thousands of lines, with each one, in 99.9% of the cases, saying that everything worked...