The more recent releases of Media Browser support a SQLite based database backend, however, this feature is disabled by default as it is still considered experimental. It does have some known issues as illustrated here:
http://community.mediabrowser.tv/permalinks/1891/strange-watched-behavior-in-2-2-3
So, if you’re willing to put up with a few bugs, go ahead and download this zip archive:
MediaBrowserSQLite.zip (298.03 kb)
This archive contains the two files required for enabling SQLite support in Media Browser. Place these in:
%ProgramData%\MediaBrowser
Then edit "MediaBrowserXml.config" so that the "EnableExperimentalSqliteSupport" entry looks like this:
<EnableExperimentalSqliteSupport>True</EnableExperimentalSqliteSupport>
You may also want to delete your "Cache" and "ImageCache" folders as, I believe, switching to SQLite will create a completely new set of files.