When you try to save a file such as a Microsoft Excel
workbook that you opened by using a universal naming convention (UNC) path, you
may receive an error message that is similar to one of the following:
Cannot read file. File is locked
Event Viewer may contain the following event:
Event Type: Information
Event Category: None
Event ID: 26
Description: Application popup: Windows - Delayed Write Failed : Windows
was unable to save all the data for the file
name_of_the_file_you_want_to_save. The data has been
lost. This error may be caused by a failure of your computer hardware or
network connection. Please try to save this file elsewhere. For more
information, see Help and Support Center at
This problem occurs when the redirector flushes the contents
of the file, and writes to a file handle with read-only access instead of to a
file handle with write access. When the redirector received an opportunistic
lock break to none, it purged the cache for the file, but did not uninitialize
the cache for the file. The redirector also needed to purge and uninitialize
when the set end of file occurs because the opportunistic lock break is
asynchronous. Because it did not uninitialize the cache for the file, it wrote
to the incorrect file handle.
Service pack information
To resolve this problem, obtain the latest service pack for Microsoft Windows XP. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:
How to obtain the latest Windows XP service pack
A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.
If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix. Note
If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note
The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language. The English version of this fix has the file attributes
(or later) that are listed in the following table. The dates and times for
these files are listed in coordinated universal time (UTC). When you view the
file information, it is converted to local time. To find the difference between
UTC and local time, use the Time Zone
tab in the Date and Time tool in Control Panel.
Windows XP SP1, Windows XP Tablet PC Edition
Date Time Version Size File name
30-Jan-2003 21:41 5.1.2600.1164 400,896 Mrxsmb.sys
30-Jan-2003 21:41 5.1.2600.1164 154,880 Rdbss.sys
Windows XP 64-Bit Edition
Date Time Version Size File name
30-Jan-2003 21:41 5.1.2600.1164 1,259,392 Mrxsmb.sys
30-Jan-2003 21:41 5.1.2600.1164 489,216 Rdbss.sys
This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
How to back up and restore the registry in Windows
To work around this problem, disable opportunistic
locking on the file server:
- Click Start, and then click
- In the Open box, type
regedit, and then press ENTER.
- In Registry Editor, locate the following subkey in the
- In the right pane, click EnableOplocks,
and then press ENTER.
- In the Value data box, type
0, and then press ENTER.
- Quit Registry Editor.
has confirmed that this is a problem in the Microsoft products that are listed
at the beginning of this article.
This problem was first corrected in Microsoft Windows XP Service Pack 2.
For additional information about opportunistic
locking, click the following article number to view the article in the
Microsoft Knowledge Base:
Configuring Opportunistic Locking in Windows 2000
A trace of this problem shows that the file is
opened at least two times, and shows the system improperly writing to the
read-only file handle. A trace that shows this problem is similar to the
96 CLIENT SMB: C NT create & X, File = \newshare.xls
SMB: Desired Access = 0x00020089
(Read Data,Read EA,Read Attributes)
97 SERVER SMB: R NT create & X, FID = 0x5
SMB: Oplock Level = Batch
<content removed that displays the client program reading and locking the file, but the file is not closed>
450 CLIENT SMB: C NT create & X, File = \newshare.xls
SMB: Desired Access = 0x0002019F
(Read/Write Data, Read/Write EA, Read/Write Attributes)
451 SERVER SMB: R NT create & X, FID = 0xc007
SMB: Oplock Level = NONE
<content removed that displays the client program reading, locking, writing and flushing data on this file handle>
585 CLIENT SMB: C write & X, FID = 0x5, Write 0xc00 at 0x00005000
PID = 0xFEFF TID = 0x1002 MID = 0x4400 UID = 0x0801
586 SERVER SMB: R write & X - NT error, System, Error, Code = (34) STATUS_ACCESS_DENIED
The process identifier (PID) of 0xFEFF in frame 585 represents
the client system process that is using the read-only file handle. It does not
show the client program writing the data to disk.