PRB: Error "3050 Could Not Lock File" When You Connect to a Jet Database on a Novell Server

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This article was previously published under Q305995

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SYMPTOMS

When you try to use Data Access Objects (DAO) to connect to a Microsoft Jet database on a Novell fileserver, you may receive the following error message:

3050 Could not lock file.

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CAUSE

This problem occurs because Novell fileservers have a maximum number of locks setting, and Jet may use a high number locks when it reads or writes an .mdb file.

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RESOLUTION

There are several ways to work around this behavior:

Use Regedit.exe or Regedt32.exe to edit the Windows Registry, and permanently change the MaxLocksPerFile value.
Use the SetOption method of the DBEngine object to temporarily change the MaxLocksPerFile value in the code.

Method 1: Change MaxLocksPerFile in the Windows Registry

Important 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:

322756 (http://support.microsoft.com/kb/322756/ ) How to back up and restore the registry in Windows

From the Windows Start menu, click Run, type Regedt32.exe, and then click OK to start Registry Editor.
Locate the MaxLocksPerFile value under the following key in the registry:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Jet\4.0\Engines\Jet 4.0
NOTE: If the MaxLocksPerFile value does not exist, you must create it.
Decrease the MaxLocksPerFile value.
Quit Registry Editor.

NOTE: This method changes the Windows Registry setting for all applications that use the Microsoft Jet database engine version 4.0.

Method 2: Use SetOption to Change MaxLocksPerFile Temporarily

Microsoft provides programming examples for illustration only, without warranty either expressed or implied, including, but not limited to, the implied warranties of merchantability and/or fitness for a particular purpose. This article assumes that you are familiar with the programming language being demonstrated and the tools used to create and debug procedures. Microsoft support professionals can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific needs.
If you have limited programming experience, you may want to contact a Microsoft Certified Partner or Microsoft Advisory Services. For more information, visit these Microsoft Web sites:

Microsoft Certified Partners - https://partner.microsoft.com/global/30000104 (https://partner.microsoft.com/global/30000104)

Microsoft Advisory Services - http://support.microsoft.com/gp/advisoryservice (http://support.microsoft.com/gp/advisoryservice)

For more information about the support options that are available and about how to contact Microsoft, visit the following Microsoft Web site:http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS (http://support.microsoft.com/default.aspx?scid=fh;en-us;cntactms) The SetOption method temporarily overrides values for the Microsoft Jet database engine keys in the Windows Registry. The new value remains in effect until you change it again or until the DBEngine object is closed.

The following code sample sets MaxLocksPerFile to 128 before it runs an update operation inside a transaction:

Sub MDBUpdate()
   On Error GoTo MDBUpdate_Error
   Dim db As DAO.Database, ws As DAO.Workspace

   ' Set MaxLocksPerFile.
   DBEngine.SetOption dbMaxLocksPerFile, 128

   Set db = CurrentDb
   Set ws = Workspaces(0)

   ' Perform the update.
   ws.BeginTrans
   db.Execute "UPDATE TableName SET Field1 = 'Updated Field'", _
         dbFailOnError


   ws.CommitTrans

   db.Close
   MsgBox "Done!"
   Exit Sub

MDBUpdate_Error:
   MsgBox Err & " " & Error
   ws.Rollback
   MsgBox "Operation Failed - Update Canceled"
End Sub

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STATUS

This behavior is by design.

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APPLIES TO

Microsoft Data Access Objects 3.51
Microsoft Data Access Objects 3.6

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kberrmsg kbjet kbprb KB305995

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Retired KB Content Disclaimer

This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.

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