The rtl8139.sys process is a component system file bundled with the other system drivers, program files and DLL modules that are required by the firmware and driver software components of certain Realtek networking devices. The Realtek RTL8139-based PCI Fast Ethernet Adapter NT Driver module specifically deploys the rtl8139.sys process as one of its system driver resources for supported versions of Windows-based systems. The rtl8139.sys file is included in the installer distribution packages of associated Realtek firmware and driver software resources, which also means the rtl8139.sys file is installed in the system upon the installation of these Realtek firmware and driver software components. The rtl8139.sys file is referenced by the Realtek RTL8139-based PCI Fast Ethernet Adapter NT Driver module, in order for the associated Realtek firmware and driver software resource to be loaded unto the system and implement the functionalities requested by the system or the user from the corresponding Realtek networking device.

Most non-system processes that are running can be stopped because they are not involved in running your operating system. rtl8139.sys. is used by Realtek RTL8139-based PCI Fast Ethernet Adapter NT Driver Module , If you shut down rtl8139.sys, it will likely start again at a later time either after you restart your computer or after an application start. To stop rtl8139.sys, permanently you need to uninstall the application that runs this process which in this case is Realtek RTL8139-based PCI Fast Ethernet Adapter NT Driver Module , from your system.

After uninstalling applications it is a good idea to scan you Windows registry for any left over traces of applications. Registry Reviver by ReviverSoft is a great tool for doing this.

The ReviverSoft experts have not yet reviewed rtl8139.sys

A process usually a part of an installed application such as Realtek RTL8139-based PCI Fast Ethernet Adapter NT Driver Module , or your operating system that is responsible for running in functions of that application. Some application require that they have processes running all the time so they can do things such as check for updates or notify you when you get an instant message. Some poorly written applications have many processes that run that may not be required and take up valuable processing power within your computer.

We have not received any complaint about this process having higher than normal impact on PC performance. If you have had bad experiences with it please let us know in a comment below and we will investigate it further.

The first thing you should do if rtl8139.sys. is causing errors on your computer is to run a Windows registry scan with Registry Reviver If you are still seeing errors after this you should uninstall the program that rtl8139.sys, belongs to, in this case Realtek RTL8139-based PCI Fast Ethernet Adapter NT Driver Module