Computer networks really cannot do without the presence of the mup.sys file. However, errors in this crucial file can prevent a computer from booting correctly, or booting at all.
HOW DO I HAVE MUP.SYS ON MY COMPUTER?
Mup.sys is used only by more recent operating systems in the Windows range --Windows XP, Windows NT, Windows 2000, and Windows Vista. The file helps in the functioning of a part of the operating system called a Multiple UNC Provider (MUP). It is part of a software system that helps networked computers communicate with one another to share files and peripheral components such as printers and scanners.
UNC stands for Universal Naming Convention -- this phrase refers to how a network of computers using the same operating system uses a common language to describe the locations of resources used by the network, such as shared files and peripherals. For all of us lay people, it means that the locations of the resources stored on a computer are described in the same way for each resource.
For example, when studying the number of files in your hard drive and click on a folder, the location of the folder on your hard drive is listed in an address bar. If you click on a folder or file, the location of the file may show up as something like C:foldernamefilename. This structure is used for every file and folder on a computer, as well as peripheral resources such as scanners and printers.
Would this reveal something about how the Multiple UNC Provider system works? When a program on a networked computer tries to access a shared resource, that computer has to use a UNC path (the path refers to the location of the resource). The access request is forwarded to the Multiple UNC Provider, which then redirects the request according to which computer on the network is making it.
The Multiple UNC Provider, therefore, is part of a system that allows networked computers to communicate with one another in a uniform manner.
HOW DOES MUP.SYS CAUSE ERRORS?
Errors in mup.sys are attributable to corruption in the system file, or a bug in the Windows operating system that relates to the mup.sys file. These errors may prevent mup.sys from loading correctly on your computer. The problem with this is that Windows tries to load mup.sys whenever you put on your computer, whether your computer is part of a network or not.
Therefore, if the file is corrupted to the extent that it cannot be completely loaded, your computer will either crash or start rebooting every time it attempts to load the mup.sys file. In most cases, this happens even when the computer is booted in safe mode.
CAN MUP.SYS CAUSE OTHER ERRORS?
Aside from file corruption errors as described above, mup.sys may occasionally cause other types of errors, depending on your operating system and configuration.
An outdated or corrupted mup.sys file might be causing a variety of non-specific network errors, most commonly in Windows 2000 and Windows NT. These may include errors in Distributed File System connections between domain controllers and client computers, as well as more general network errors in networks running any XP, 2000, NT or Vista version of Windows.
In most cases, the root cause of such errors, including most of the following, lies in using an operating system version that has not been updated.
Stop 0x50 Error (Windows NT 4.0)
This error occurs if your sound scheme is set to "No Sounds". The system finds it difficult to follow this -- it searches for a file called "close.wav" on the network at computer shutdown, even though sound has been set to off and the file will not be used. When this happens, a bug in the mup.sys file leads to error messages. This may happen whenever the computer is turned off.
Stop: 0x0000000a Error (Windows NT 4.0 Terminal Server Edition Service Pack 6a)
This happens to be a common error. The error is regardless of system configuration or what applications are currently running. However, only computers running the above version of Windows NT may fall prey to this error type.
Event ID 2012 (Windows NT 4.0, with Service Pack 3)
An outdated mup.sys file may occasionally be the cause of an Event ID 2012 Network Error in computers running this version of Windows NT. We see such errors when running an application that uses Btrieve engine version 6.15 (Btrieve is a database that uses a method of storing data that provides fast retrieval times).
Non-responsive Network (Windows 2000, SP1 or 2)
An error in mup.sys may occasionally cause computers across a network to become non-responsive when a networked computer disconnects from the Distributed File System.
System Error 53 (Windows 2000, Windows NT 4.0)
This error can occur when using a version of either operating system that may be rather old. The error occurs due to incompatibility between mup.sys and the Distributed File System.
