The following is a list of troubleshooting steps to follow if you are having MDAC setup issues.
Shut down all Windows NT services and Windows applications that are using MDAC.
When you run MDAC setup it installs new data access DLLs and also updates existing system DLLs on the system. If one or more of these DLLs is in use by an application, it can lead to unsuccessful MDAC setup. Before running the MDAC setup program Mdac_typ.exe, close all applications that use MDAC with Windows NT services and close all applications on the computer. This is the number one reason that Microsoft Product Support Services has determined can cause MDAC setup to fail. In many cases, simply closing all applications and services using MDAC and re-running the MDAC installer will properly configure MDAC after a failed setup. The following Microsoft applications and services use MDAC components:
Internet Information Server
Microsoft Office (All Office Applications)
Outlook and Outlook Express
Visual Studio (All Development Products)
Note that the earlier list details the most common products that use MDAC. For best results, close all user applications before running MDAC.
To completely make sure that no MDAC DLLs are in use on the system, you can
run a popular third-party utility called ListDLLs which is available from the following Web site:
Using the search facility in this utility, search for Odbc32.dll, Oledb32.dll, and Msado15.dll. Any process that is using one of these DLLs is using MDAC components and should be closed prior to installing MDAC.
Make sure that you are logged on as an Administrator on Windows NT and Windows 2000.
Note On computers that are running Windows 95, Windows 98, or Windows Millennium Edition, this step does not apply. To properly install DLLs, and to create registry settings, the MDAC installer requires that you are logged in with Administrator privileges on a Windows NT computer. Failure to do so may result in a failed MDAC setup, because MDAC will not have the proper security privileges to write DLLs to the system folder or make registry changes. You may see the following error messages:
Setup Error 168 - Setup has encountered a problem updating your system registry
Insufficient Privileges - You do not have sufficient privileges to install here
Disable any anti-virus or disk security software applications running on the computer.
Many anti-virus and disk security software applications run memory resident programs that can interfere with the installation of other software. Before installing MDAC, temporarily disable any anti-virus and disk security software applications running on the computer.
Ensure you have adequate hard drive space to install MDAC
MDAC requires at least 40 MB of free hard-drive space in order to install correctly.
Note that MDAC installs files into the Program Files folder as well as into the system folder (Windows\System on a Windows 95, Windows 98, or Windows Millennium Edition-based computer or WinNT\System32 on a Windows NT computer). In most cases, these folders will be located on the C: drive, but the folders can be set up on any drive on the computer.
Make sure you have a valid TEMP folder defined and that there is adequate space on the TEMP drive. (TEMP Drive refers to a drive where TEMP Folder is.)
When the MDAC installer starts running, it extracts all of the MDAC files into the TEMP drive defined on your system. Therefore you will need at least 40 MB of free hard-drive space on the drive where TEMP resides. You can determine the location of your TEMP drive by opening up a MS-DOS command prompt and entering SET and then clicking Enter. A list of environment variable settings should appear and in the list you should see TEMP= and TMP= followed by a folder location such as C:\TEMP or C:\WINDOWS\TEMP. The TEMP folder listed must exist and be located on a drive with at least 40 MB of free space.
Make sure that Windows 95 computers have DCOM95 installed.
All Windows 95 computers need to have DCOM95 installed before running MDAC setup. You can download DCOM95 from the following Web location:
Clustered SQL Server do's, don'ts, and basic warnings
MDAC Setup has failed. What should I do now?
If you follow the above steps and MDAC still fails to install, here are some additional trouble-shooting steps you can try:
Quiet mode failing If MDAC setup has failed while running in quiet mode (for example some applications may install MDAC silently as part of their installation program). Try to run the standard mode installation of MDAC on the computer.
The general recommendation is to download the latest version of MDAC from
and install this first before re-running the silent installer (or application setup that uses the MDAC silent installer).
Manually extract Mdac_typ.exe. When you run the MDAC setup, it extracts all the setup files into the system defined TEMP directory first before continuing. You can manually extract the MDAC files yourself and run the setup directly as well. This is a good trouble-shooting step if you think that the computer may not have a properly defined TEMP folder. To extract the MDAC setup files, copy the MDAC installer (Mdac_typ.exe) to the C:\ root folder and run the following command from Start menu click Run:
C:\mdac_typ.exe /c /t:c:\MDACSetup
The above command starts the MDAC installer and extract the files into a folder named C:\MDACSetup (it automatically creates the folder if it does not exist). Once the files are extracted, the MDAC installer quits (it does not attempt to install MDAC). Once the files are extracted, run the extracted Setup.exe inside the C:\MDACSetup folder to start the MDAC installer in "extracted mode".
Use logging. The MDAC setup program has advanced setup logging capabilities. You can run MDAC Setup with log file generation and then examine the log file to determine what portion of MDAC setup failed. This log file will also contain any errors that occur during installation. In order to run MDAC setup with logging, first extract out the MDAC setup program as detailed in the earlier section and then run the following command from Start menu click Run:
C:\MDACSetup\Setup.exe /gc C:\Mdaclog.txt
Note you can avoid the extraction step by running the following command directly:
C:\Mdac_typ.exe /C:"Setup /GC C:\Mdaclog.txt"
Once the setup is complete you can examine c:\Mdaclog.txt in notepad to gain more information about where the setup failed.
Cannot find Setup.lst. If the folder that you are running MDAC setup from, has another Setup.exe in it, MDAC setup displays the following error:
Setup cannot access the required initialization file '\FolderName\Setup.lst'
The workaround for this problem is to remove or rename the Setup.exe file or start MDAC setup from different folder.
Use the Dasetup.log file (MDAC 2.6), usually located in the root of the Windows directory, to determine the last call that failed in the MDAC setup. If the last call shows the following:
the path for the SQL Server ODBC driver in the registry entry is either invalid or is pointing to a network driver. This causes the MDAC installation to fail. Go to the following registry entry:
and change the "driver" and "setup" values to point to the local Windows\System (Win9.x) or Windows\System32 (WinNT and Win2000) directory. Then restart MDAC setup.
Uninstall MDAC. In rare circumstances you may need to completely un-install MDAC before continuing with re-installation. For example, if you want to remove a later version of MDAC and install an older version of MDAC, you cannot over-install the older version (the MDAC installer will not over-write a newer DLL version with an older version dll). Also in cases where all of the above recommendations fail on a normal setup, re-configuring MDAC is a good next step.
The MDAC setup program for MDAC versions before 2.6 does not have a built-in un-install feature. Microsoft Product Support has a Component Checker tool designed to diagnose and re-configure (un-install and re-install) MDAC.
Note MDAC 2.5 comes preinstalled on computers with Windows 2000 and Windows Millennium Edition. Currently, you cannot use Component Checker to uninstall MDAC from a computer running Windows 2000 or Windows Millennium Edition. MDAC 2.6 provides its own uninstall functionality.
For more information, click the following article number to view the article in the Microsoft Knowledge Base:
Frequently asked questions about the installation of Microsoft Data Access Components (MDAC)
If you run into an installation issue with MDAC on Windows 2000 or Windows Millennium Edition, please contact Microsoft Product Support Services. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:
Component Checker: Diagnose problems and reconfigure MDAC installations
If you are still experiencing problems with MDAC installation or if you receive an error message that your installation has not passed Windows Logo testing to verify the compatibility of the installation with the version of Windows, visit the following Microsoft Knowledge Base article for additional troubleshooting steps:
I think MDAC Setup worked. How can I verify that MDAC is set up correctly?
The following trouble-shooting tests provide some simple methods to check if MDAC is installed correctly. Since MDAC is composed of a large number of inter-dependant DLLs, the only real test of MDAC setup success is to fully test your MDAC using applications to ensure everything is working properly. The following tests do not require any specific applications installed on the computer, so they are good for a quick MDAC setup verification on any machine.
First check that the ODBC Administrator is working. Open the Control Panel and select the ODBC Data Sources icon. (In Windows 2000 go to Control Panel, select Administrative Tools and click Data Sources (ODBC) ). A dialog box should appear with the title "ODBC Data Source Administrator". Attempt to create a new ODBC datasource via the following steps:
Select the System DSN tab in the ODBC Administrator.
Click Add to create a new ODBC data source
Select Microsoft Access Driver (*.mdb) from the list and click Finish.
Type TEST in the Data Source Name edit box.
Type in C:\TEST.MDB in the Database Name edit box and click OK. At this point a message box should appear indicating that a database was successfully created. Click OK.
Click OK again to close the ODBC Microsoft Access Setup dialog box and create a new ODBC datasource.
Next click OK to close the ODBC Administrator dialog box.
If the earlier steps complete successfully, you can be fairly certain that the ODBC core files and ODBC administrator are set up correctly.
Next, create a Microsoft DataLink file and test a connection to the TEST datasource created earlier through the following steps:
Right-click on the computer's desktop and from the New menu select Microsoft Data Link. This should create a new file on the desktop named "New Microsoft Data Link.udl". In Windows 2000 right-click your desktop and create a text file and rename it Test.udl.
Double-click this file to open the Data Link Properties dialog box.
Select TEST (the data source you created earlier) in the "Use data source name" drop-down box.
Click Test Connection button. At this point you should see a message box indicating "Test connection succeeded".
If the earlier steps complete successfully, you have performed test of both OLE DB and ODBC as well as the Access ODBC driver.
In order to verify that ADO and RDS are installed correctly, you need to run an application that uses ADO or RDS on the computer. You can use the Component Checker tool described in the previous section.
If MDAC Setup continues to fail after carrying out the above stated precautions and troubleshooting techniques, please contact Microsoft Product Support Services for professional help. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:
The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.
Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.