VB6 + ODBC + Access MDB: Setup Tricks

1️⃣ ODBCAD32 (64-bit) vs ODBCAD32 (32-bit)

• 64-bit version: Located at C:\Windows\System32\odbcad32.exe ➤ Manages 64-bit DSNs—not usable by VB6 apps.

• 32-bit version: Located at C:\Windows\SysWOW64\odbcad32.exe ➤ Manages 32-bit DSNs—required for VB6, which is 32-bit.

✅ Always use the 32-bit ODBC Administrator for VB6 compatibility.

2️⃣ User DSN vs System DSN

• User DSN: ➤ Stored per user in HKEY_CURRENT_USER. ➤ Only visible to the user who created it. ➤ Can access mapped drives like G:.

• System DSN: ➤ Stored in HKEY_LOCAL_MACHINE. ➤ Visible to all users. ➤ Requires admin rights to create/edit. ➤ Cannot see mapped drives unless created in same session.

⚠️ If both exist with the same name, User DSN takes priority.

3️⃣ Logical Drive vs UNC Path

• Mapped drives (e.g., G:): ➤ Session-specific; may disappear in elevated/admin mode. ➤ Not reliable for System DSNs.

• UNC paths (e.g., \\Server\Share\YourDB.mdb): ➤ Always accessible across sessions and users. ➤ Recommended for both System DSNs and DSN-less connections.

🛠️ Use Registry Editor to manually set DBQ to a UNC path if the GUI doesn’t allow it.

🛠️ Manually Setting DBQ to a UNC Path in the Registry

When the ODBC Administrator (odbcad32.exe) doesn't allow UNC paths in the Select Database dialog, you can manually set the database path by editing the registry.

📍 Registry Location for System DSNs (32-bit):

Code

HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\ODBC\ODBC.INI\YourDSNName

🔧 Steps:

1. Open Registry Editor (regedit.exe) as Administrator.

2. Navigate to the key above, replacing YourDSNName with the name of your DSN.

3. In the right-hand pane, look for a string value named DBQ.

   • If it doesn’t exist, right-click → New > String Value → name it DBQ.

4. Double-click DBQ and enter your full UNC path:

   Code

   \\ServerName\ShareName\YourDatabase.mdb
   

5. Close Registry Editor.

✅ Why This Works

• The DBQ value tells the Access ODBC driver where to find the .mdb file.

• UNC paths are session-independent and work reliably across users and privilege levels.

• This bypasses the GUI limitation and ensures your VB6 app can connect without relying on mapped drives.