What is serial?

The genuine serial.sys file is a software component of Microsoft Windows Operating System by Microsoft.
This device driver supports non-plug and play serial devices. Serial.sys allows the operating system to interact with the serial device and permits functionality. Before the advent of USB peripherals, this driver was used for a variety of devices. Founded in 1975 in New Mexico, Microsoft is now one of the largest software corporations in the world. Currently headquartered in Washington, the flagship Windows operation system is the most utilized OS in the world.

Serial stands for Serial Device Driver

Serial.sys is a Windows driver. A driver is a small software program that allows your computer to communicate with hardware or connected devices. This means that a driver has direct access to the internals of the operating system, hardware etc. The free file information forum can help you determine if serial.sys is a Windows system file or if it belongs to an application that you can trust.

Run a free scan to check for serial drivers in need of updating

Serial.sys file information

The process known as Serial Device Driver or Brotehr Serial I/F Driver belongs to software Microsoft Windows Operating System by Microsoft ( or Brother Industries (

Description: The original serial.sys is an important part of Windows and rarely causes problems. The serial.sys file is located in the C:\Windows\System32\drivers folder. Known file sizes on Windows 10/8/7/XP are 83,456 bytes (23% of all occurrences), 64,512 bytes and 4 more variants. 
The driver can be started or stopped from Services in the Control Panel or by other programs. The program has no visible window. There is no detailed description of this service. The serial.sys file is a Microsoft signed file. The application is not active. serial.sys appears to be a compressed file. Therefore the technical security rating is 4% dangerous, however you should also read the user reviews.

Recommended: Identify serial.sys related errors

Important: Some malware disguises itself as serial.sys, particularly when not located in the C:\Windows\System32\drivers folder. Therefore, you should check the serial.sys process on your PC to see if it is a threat. We recommend Security Task Manager for verifying your computer's security. This was one of the Top Download Picks of The Washington Post and PC World.


User Comments

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Summary: Average user rating of serial.sys: based on 5 votes with 7 user comments. 5 users think serial.sys is essential for Windows or an installed application. 6 users don't grade serial.sys ("not sure about it").

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Best practices for resolving serial issues

A clean and tidy computer is the key requirement for avoiding problems with serial. This means running a scan for malware, cleaning your hard drive using 1cleanmgr and 2sfc /scannow, 3uninstalling programs that you no longer need, checking for Autostart programs (using 4msconfig) and enabling Windows' 5Automatic Update. Always remember to perform periodic backups, or at least to set restore points.

Should you experience an actual problem, try to recall the last thing you did, or the last thing you installed before the problem appeared for the first time. Use the 6resmon command to identify the processes that are causing your problem. Even for serious problems, rather than reinstalling Windows, you are better off repairing of your installation or, for Windows 8 and later versions, executing the 7DISM.exe /Online /Cleanup-image /Restorehealth command. This allows you to repair the operating system without losing data.

To help you analyze the serial.sys process on your computer, the following programs have proven to be helpful: ASecurity Task Manager displays all running Windows tasks, including embedded hidden processes, such as keyboard and browser monitoring or Autostart entries. A unique security risk rating indicates the likelihood of the process being potential spyware, malware or a Trojan. BMalwarebytes Anti-Malware detects and removes sleeping spyware, adware, Trojans, keyloggers, malware and trackers from your hard drive.

Other processes

serial.sys [all]