> there should be one utility page that will help you identify the missing pages on the disk
> and allow you to easily remove the orphan documents, good point and we will see if we can do something about this.
you could change the pages list to show in red color any broken page URLs (or the whole row, but guess the red URL [and more redish on mouse over or something] points the user to the problem [the missing page / broken URL] exactly mentally). Refreshing the list (think there is such button) would update the colours in case you've manually edited files in between.
BTW, Windows does have shell notifications that one can use to see folder changes (there could even be ASP.net API to wrap that functionality of folder-change-monitoring, but not sure) and could even refresh the list remotely on the browser (say using SingalR), but don't need to go to that extent
Thanks for the pointer to the full-test search functionality, will look into enabling it (does it use Windows Search or the older Indexing Service [think that is usually turned off in the OS though in recent Windows] for that or something for that or some custom engine?)