How to Fix VB6 Excel Automation Error 80010105 After an Office Upgrade
Question details
Users encounter runtime error 80010105 when running Visual Basic 6 (VB6) automation scripts after upgrading their Microsoft Office installation.
- Product
- Microsoft Excel
- Device & OS
- not provided
- Scenario
- Running a legacy VB6 application that automates Excel tasks, such as creating or saving workbooks, following a recent Microsoft Office version upgrade.
- Observed behavior
- The VB6 application throws Automation error 80010105 and fails to execute the Excel automation code, preventing workbooks from being generated or saved.
Verify whether your newly installed Microsoft Office version is 32-bit or 64-bit, and ensure you have administrative privileges to modify application references and COM add-ins.
Update VB6 Project References and Verify Bitness
Correct mismatched library references and architecture differences between the old and new Office installations.
Visual Basic 6 is inherently a 32-bit application. If your recent Office upgrade installed a 64-bit version of Excel, the out-of-process COM automation may fail or require specific late-binding configurations. Additionally, the project may still be pointing to the older Excel Object Library.
Open your VB6 project, navigate to the 'Project' menu at the top, and select 'References'.
Look for any items marked as 'MISSING: Microsoft Excel Object Library' and uncheck them to break the broken link.
Scroll down the list and check the box for the current 'Microsoft Excel xx.0 Object Library' corresponding to your newly installed Office version.
Open Excel, go to 'File' > 'Account' > 'About Excel' to check if it is 64-bit. If it is, consider utilizing late binding (using CreateObject instead of specific library references) in your VB6 code.
Disable Conflicting Excel Add-ins
Identify and disable third-party add-ins that might interfere with background COM automation.
Try WPS Office for Reliable Spreadsheet Management
If Microsoft Office upgrades and complex COM dependencies are causing persistent automation errors, consider switching to WPS Office. It provides an excellent, lightweight alternative with high compatibility for standard spreadsheet formats.
Frequently Asked Questions
What causes automation error 80010105 in VB6?
This runtime error is typically caused by a mismatch in COM object references, conflicts with installed Excel add-ins, or differences between 32-bit and 64-bit application architectures after an Office upgrade.
Does upgrading Office from 32-bit to 64-bit break VB6 applications?
Yes, VB6 is a 32-bit development environment. If it attempts to interact with a 64-bit version of Excel using early binding (referencing the specific library), automation errors often occur. Transitioning to late binding can resolve many of these cross-architecture issues.
How can I safely test if my Excel automation code is working again?
Create a simple test subroutine in your VB6 application that only creates an Excel application object and makes it visible (e.g., set objExcel.Visible = True). If this basic code runs without error 80010105, your core application references are fixed.
