Bug Check 0x103: MUP_FILE_SYSTEM

The MUP_FILE_SYSTEM bug check has a value of 0x00000103. This bug check indicates that the multiple UNC provider (MUP) has encountered invalid or unexpected data. As a result, the MUP cannot channel a remote file system request to a network redirector, the Universal Naming Convention (UNC) provider.


This article is for programmers. If you're a customer who has received a blue screen error code while using your computer, see Troubleshoot blue screen errors.


Parameter 1 identifies the type of violation.

Parameter 1 Parameter 2 Parameter 3 Parameter 4 Cause of error


The address of the pending IRP.

The address of the file object whose file context could not be found.

The address of the device object.

The MUP could not locate the file context that corresponds to a file object. This typically indicates that the MUP is seeing an I/O request for a file object for which MUP did not see a corresponding IRP_MJ_CREATE request. The likely cause of this bug check is a filter driver error.


The address of the expected file context.

The address that was actually retrieved from the file object.


A file context is known to exist for the file object, but was not what was expected (for example, it might be NULL).


The address of the IRP context.

The IRP completion status code.

The driver object of the UNC provider that completed the IRP (might be NULL).

The IRP completion status was unexpected or invalid.

This bug check occurs only when you are using a Checked Build of Windows and should only be caused by file system filter drivers that are attached to legacy network redirectors. Checked builds were available on older versions of Windows before Windows 10, version 1803. Legacy redirectors use FsRtlRegisterUncProvider to register with MUP. This bug check detects filter drivers that return an NTSTATUS that is not STATUS_SUCCESS in IRP_MJ_CLEANUP or IRP_MJ_CLOSE requests.


Address of the IRP

Address of the file object

The file context for the file object

An I/O operation was started on a file object before the create request for the file object was completed.


The MUP maintains context information on a per-file object basis for all file objects it handles.