eMule system files explained
Fileinfo.ini: Comments or Ratings for your own shared files.
Category.ini: Settings of your categories like name, comment and colour coding.
Ipfilter.dat: IP ranges and access levels to be filtered.
Onlinesig.dat: The server eMule is connected to – up / download statistics. Can be used by IRC scripts or signature images.
Preferences.dat: It keeps the user hash. This is a value calculated at eMule’s first start and is used to identify this client in the network. Used for credit system and friends.
Cryptkey.dat: It contains the unique 384 bit private RSA key of your client to verify your userhash. If you delete this file, make sure to also delete preferences.dat which stores your userhash.
Sharedir.dat: Holds the paths to all of your shared directories.
Staticservers.dat: Static servers never change their IP and are theoretically always online in the network. These servers can be added to staticservers.dat by the context menu (right mouse button) of the server list.
Addresses.dat: eMule updates its server list at startup if valid addresses to server.mets are provided in this file. Options -> Server offers a button to edit this list and the option for updating at start up. The file may contain multiply entries (one on each line) but only the first address to deliver a valid server.met is used.
AC_SearchStrings.dat: Each search string that has been used is recorded and an auto-completing is offered if a new search matches previous ones.
AC_ServerMetURLs.dat: Same file as the the one above. The only difference is that this one is used to store entered URL to server.met files. Mind that many sites regularly change the addresses to their server.mets.