Indexing Service is no longer supported as of Windows XP and is unavailable for use as of Windows 8. Instead, use Windows Search for client side search and Microsoft Search Server Express for server side search.
The UsnReadTimeout entry is the maximum interval of time for the indexing process to wait before processing change notifications in the USN journal.
|Default:||300 (5 minutes)|
|Range:||0 - 43200 (12 hours)|
The processing of change notifications proceeds when either an interval of time equal to the value of the UsnReadTimeout entry has passed (and there are entries in the USN journal) or the size of the USN journal reaches the value of the UsnReadMinSize entry.