Reasons why device open fails

Reasons why device open fails

Article ID: Q400001

The information in this article applies to:

Direct I/O, version 4.0, 4.1, 4.2, 4.3, 4.4

SUMMARY

There are a number of reasons why a call to open a handle to a Direct I/O device might fail. This article tries to give the background info and possible actions to be taken.

MORE INFORMATION

When you are writing your own application using Direct I/O the first thing to do is to open a device handle to Direct I/O. This is done with a call to the Win32API function CreateFile(). This call might fail for a number of reasons returning you the value INVALID_HANDLE_VALUE (-1). To get a hint what failed you should immediately call the function GetLastError() which will return an error code.
Below you will find a table with the error codes that apply to Direct I/O:

Error	Code	Reason	Action
2	ERROR_FILE_NOT_FOUND	The driver is not running.	Start the driver using the control panel or by typing `NET START DIRECTIO`.
5	ERROR_ACCESS_DENIED	Your process is not allowed to access Direct I/O (see security configuration).	Add your process to the list of allowed processes. Check article Q400002 for possible problems.
8	ERROR_NOT_ENOUGH_MEMORY	Not enough memory to complete this operation.	Reboot.
317	ERROR_MR_MID_NOT_FOUND	This is a misleading error because the kernel driver error is STATUS_ILL_FORMED_SERVICE_ENTRY which exactly describes the problem: A registry entry of Direct I/O is damaged. But Microsoft didn't manage to translate this error to user mode.	Reinstall Direct I/O.
478 1450	ERROR_NO_SYSTEM_RESOURCES	The resources you selected conflict with others already in use by Windows NT.	Resolve the conflict using the control panel.
1793	ERROR_ACCOUNT_EXPIRED	The evaluation time of Direct I/O is over.	Please license your copy or uninstall Direct I/O.

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