Microsoft KB Archive/305995

= PRB: Error &quot;3050 Could Not Lock File&quot; When You Connect to a Jet Database on a Novell Server =

Article ID: 305995

Article Last Modified on 11/23/2006

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APPLIES TO


 * Microsoft Data Access Objects 3.51
 * Microsoft Data Access Objects 3.6

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This article was previously published under Q305995



IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry



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.



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.



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
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

 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
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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 &quot;UPDATE TableName SET Field1 = 'Updated Field'&quot;, _ dbFailOnError

ws.CommitTrans

db.Close MsgBox &quot;Done!&quot; Exit Sub

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



STATUS
This behavior is by design.

Keywords: kberrmsg kbjet kbprb KB305995

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