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What is Fastfat?

Fastfat.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 OS, hardware etc.
The free file information forum can help you determine if Fastfat.sys belonging to the Windows system or an application you can trust.

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

Fastfat.sys file information

The process known as Fast FAT File System Driver belongs to software Microsoft Windows Operating System by Microsoft (www.microsoft.com).

Description: The original Fastfat.sys is an important part of Windows and rarely causes problems. Fastfat.sys is located in the folder C:\Windows\System32\drivers. Known file sizes on Windows 7/XP are 143,360 bytes (78% of all occurrences), 143,744 bytes, 145,152 bytes or 144,768 bytes. http://www.file.net/process/fastfat.sys.html 
The driver can be started or stopped from Services in the Control Panel or by other programs. The file is a Windows system file. The program is not visible. There is no detailed description of this service. The Fastfat.sys file is a Microsoft signed file. Fastfat.sys seems to be a compressed file. Therefore the technical security rating is 1% dangerous, however also read the users reviews.

Recommended: Identify Fastfat.sys related errors

Important: Some malware disguises itself as Fastfat.sys, particularly when not located in the C:\Windows\System32\drivers folder. Therefore, you should check the Fastfat.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

file used in raid or scsi setups in Microsoft OS's
  James Urwiller, Service Manager Computer Warehouse #4   (further information)
I deleted fastfat.sys off my laptop and now everytime i plug in a protable drive or digital camera it prompts me to format the external drive.
When not loaded, cannot read from a floppy or USB memory stick.
when i tried installing windows after a fat32 format i get tis sot error i.e. STOP:0X00000050 ( 0XA11B7A4C,0X00000000,0XFC795AD6,0X00000002 ) fastfat.sys-Address FCF9AD6 base at FC&8D000 DateStamp 41107EB7
This is the driver for reading/writing FAT formatted drives (usually USB sticks, smaller external drives, and those devices appearing as drives such as digital cameras and mp3 players)
  Tim, Senior Electrical Engineer  
needed to mount FAT-based drives (USB sticks, floppy/tape drives)
I have a customer of mine with multiple infections. According to one of my Infectious Removal Tools C:\WINDOW\System32\dllcache/fastfat.sys is an infection.
  PC Recovery Technician.  
Essential for USB Sticks, when crash occurs at boot, remove all USB storage devices
Used by TrueCrypt when encrypted volumes are formatted with FAT. Also used, as others have said, for other FAT-formatted volumes.
  IT Fixt  
FAT kernel-level file system driver loaded via IFS for Windows NT 4.x upwards
  Some Nerd   (further information)

Rating chart

Summary: Average user rating of Fastfat.sys: based on 16 votes with 10 user comments.
13 users think Fastfat.sys is essential for Windows or an installed application. One user thinks it's probably harmless. One user suspects danger. One user thinks Fastfat.sys is dangerous and recommend removing it. One user is not sure about it.

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Fastfat scanner

Security Task Manager shows all running Windows tasks including embedded hidden functions (e.g. keyboard or browser monitoring, autostart entry). A unique security risk rating indicates the likelihood of the process being potential spyware, malware, keylogger or a Trojan.

Malwarebytes Anti-Malware detects and removes sleeping spyware, adware, trojans, keyloggers, malware and tracking threats from your hard disk. Ideal supplement to Security Task Manager.

SpeedUpMyPC scans, cleans, repairs and optimizes your computer.

Other processes

Fastfat.sys [all]