While Capcom shut down the US online servers for Outbreak on December 31, and the JP servers on June 30, 2011, fans have created a replacement server for the JP version. The server was reverse-engineered by capturing the information communicated between the game and the server while it was still running. However, because the different regions used different matchmaking services, and packets were only captured for the JP version, they have not been able to create a server compatible with the US version of the game.

"Resident Evil Online" and "Network Biohazard" were both working titles for Resident Evil Outbreak during its development.

More than 18 scenarios were originally planned for Resident Evil Outbreak, but most of them were cut, along with other additional content, or relegated to the standalone expansion Outbreak File #2. However, some of the scrapped character models can still be found in the game's data and are usable through the use of Gameshark or other such cheat device.

The first of the two Outbreak games could not be played online in Europe despite online multiplayer being the main point of the game. This was due to technical difficulties with having to work with multiple languages and different service providers. The European release was first delayed in hopes of overcoming these problems, but it was eventually decided to introduce CPU-controlled characters instead. However, the work done during this period enabled them to provide online multiplayer for the European release of File #2.

The US cover for both Outbreak and Outbreak File#2 uses the Resident Evil live-action movie title font in the name while the European and Japanese versions use the standard Resident Evil/Biohazard font.