Definition of System Log in the Network Encyclopedia.
What is System Log?
System Log is a Microsoft Windows log that records events generated by the operating system. Events logged in the system log mainly consist of information about services starting, stopping, or failing and about system device drivers that fail. Administrators cannot alter the type of information logged in the system log. You can view and manage the system log by using the administrative tool Event Viewer.

The following are three types of events that can be logged to the system log:
- Errors: Identified by a white “X” in a red circle; indicates a significant problem that might have caused data loss or the loss of some aspect of system functionality (for example, a service failing to start properly)
- Warnings: Identified by an exclamation mark in a yellow triangle; indicates a problem that might not be critical but might have an impact later (such as low disk space)
- Information: Identified by a blue letter “i” in a speech balloon; indicates a significant but harmless event such as a service starting or device driver initializing