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 MaxIndexes entry is the maximum number of persistent indexes allowed in the catalog.
|Range:||10 - 150|
Usually, a shadow merge combines all existing word lists into a new shadow index. When the total number of indexes exceeds the value of the MaxIndexes entry, a shadow merge is performed to bring the total below this number.