PRB: Error "3050 Could Not Lock File" When You Connect to a Jet Database on a Novell Server (305995)

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.

1. From the Windows Start menu, click Run, type Regedt32.exe, and then click OK to start Registry Editor.
2. 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.
3. Decrease the MaxLocksPerFile value.
4. 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 the Microsoft fee-based consulting line at (800) 936-5200. For more information about Microsoft Certified Partners, please visit the following Microsoft Web site: For more information about the support options that are available and about how to contact Microsoft, visit the following Microsoft Web site: 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