The distinguishing features of eMule are the direct exchange of sources between client nodes, fast recovery of corrupted downloads, and the use of a credit system to reward frequent uploaders.

[4] The eMule project was started on May 13, 2002 by Hendrik Breitkreuz (also known as Merkur) who was dissatisfied with the original eDonkey2000 client.

Some users have complained that it leads to a loss of active sources and subsequently slows download speed.

Other recent additions include: the ability to run eMule from a user account with limited privileges (thus enhancing security), and AICH (so that a corrupted chunk does not need to be re-downloaded entirely).

[6] The 0.47b version adds protocol obfuscation and eMule will automatically select two port numbers at random in the startup wizard.

The top-level MD4 hash, file size, filename, and several secondary search attributes such as bit rate and codec are stored on eD2k servers and the serverless Kad network.

Newer versions of eMule support AICH (Advanced Intelligent Corruption Handling).

eMule requires 10 agreeing peers regarding the SHA-1 hash, so rare files generally do not benefit from AICH.

Users who cannot be reached from the outside because they are firewalled, behind a NAT device that has not been correctly port forwarded, or whose IP address ends with a zero (e.g. 123.45.67.0)[7] get a "Low ID" from the servers.

Also, a releaser or heavy uploader that uses a releaser mod such as MorphXT or Xtreme that is forced to operate on a Low ID (hotel room, job) also will find that they will have little control over their upload priorities (especially powershares) as the servers appear to limit their connection-forwarding for each client, thus turning their upload queue to a contention situation where the first to be able to get forwarding and find an open slot gets it.

The credit system provides a major modifier to this waiting time by taking the upload and download between the two clients into consideration.

This automatically assigns a reserved upload slot for that peer so that he/she can begin downloading regardless of the Credit rating.

eMule also supports source exchanges, allowing it to substantially reduce the loads on the servers and Kad.

As a popular open source program, eMule has many variants, usually called mods.

Due to the popularity and open-source nature of eMule, some third parties have created modified versions of it, which frequently contain spyware and other malware programs.

Some fake sites ask for credit card information or require the user to sign up for a paid membership.

Some criticized VeryCD for their misleading name "Dianlv" (Chinese: 电驴; pinyin: Diàn Lǘ; lit.

[14][15] On July 29, 2017 was released a "Community Version" of eMule[16] maintained by the official forum users.