Collectioncryptkey.dat: This file only exists if you have created and signed at least one collection in eMule. It contains a unique 1024 bit RSA key, which will be used for all collections you are signing to verify that they are from the same author.

eMule.tmpl: The *.tmpl files are required for the Webinterface. They define layout and options of the displayed pages.

xx.part: Part files are unfinished downloads. eMule is able to download from more than one user at the same time, so the *.part files always have the size of finished download. Missing parts are simply filled with zero. In recent versions, and when using the NTFS filesystem, you can enable the option to share incompleted files as ‘sparse’, which prevents this behaviour and saves disk space.

xx.part.met: Every *.part file has a corresponding *.part.met file. To identify a download in the network and to check for errors each download is divided to about 9 MB parts. For each part a so called hash value is calculated. Then a new hash value is created of the complete set of these part hashes. This information together with the file name and the status of the hashes are stored in the *.part.met files.

xx.part.met.BAK: A backup of the *.part.met files is created as it is very bad if such a file gets corrupted by a crash.

eMule.log: Saves the output of the Log window in the Server pane if the appropriate option in Options -> Extended is turned on

eMule_Debug.log: Saves the output of the Debug window in the Server pane if the appropriate option in Options -> Extended is turned on

src_index.dat, preferencesKad.dat, nodes.dat, key_index.dat, load_index.dat: They are used by Kad and contain infomation about known nodes, keywords, preferences etc.

each and every file. If you delete this, eMule will have to rehash all files on the next restart.K