PRB: "Another Application is Currently Using JET File..."

• Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.1, 4.2, 5.0

SYMPTOMS

When you try to install DAO components, the following error message may appear:

   Another application is currently using JET file,
   close all applications and continue.

CAUSE

This error message can have one of following causes:

• Another application has opened one of the DAO/Jet DLL's. When a DLL is loaded in memory, Windows treats the file on the disk it was loaded from as read-only. This is by design.
• The read-only attribute of the file that is being updated has been turned on.

RESOLUTION

To resolve the first problem, if one of the DLL's that DAO is trying to update is loaded in memory, then shut down all of your applications and tell the setup program to continue. It is a good idea to perform a setup with all applications shut down for this very reason.

The second problem is not as obvious because the setup program cannot distinguish between a file with a read-only attribute set and a file that is currently loaded into memory. The setup program will not identify the specific file(s) that have read-only turned on.

Having the read-only flag set for DLL's is usually used as a low-level virus protection, but it can also hamper the operation of programs using those DLL's or attempting to upgrade them. From a DOS command prompt, go to the Windows directory and type:

   attrib -r *.* /s

You may also want to go to the \Program Files\Common Files directory and perform the same procedure because DAO/Jet and other shared components are often installed there as well.

STATUS

This behavior is by design.

Keywords          : dbDao MfcDAO MfcDatabase
Technology        : kbMfc
Version           : 4.0 4.1 4.2 5.0
Platform          : NT WINDOWS
Issue type        : kbprb