How can I update to Office 365 Access Database Engine on a machine that has Office 365 already installed?

Dear @Azali, Mark,

Welcome to Microsoft Q&A Forum!

Based on your description and the image, I can understand that you installed Microsoft 365 Access Runtime on a machine that already has Office 365 installed. After doing so, you see the error message like your image.

This happens because Access Runtime is not the full version of Access. It’s a lightweight component meant only for running existing Access applications (ACCDB/MDB files) without design capabilities. When installed alongside the full Office suite, it can override registry associations and cause Access to behave like Runtime mode, which explains why the customer cannot open Access normally. Here are several reasons that may cause:

1.Registry conflict: Installing Access Runtime on a machine with Office 365 (Click-to-Run) changes registry keys under:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\ClickToRun\REGISTRY\MACHINE\Software\ODBC\ODBC.INI

2.Runtime may have limitation: Access Runtime does not allow creating or editing databases, it only opens existing files. If the customer tries to start Access without specifying a file, they get the error.

3.ODBC entries missing: With Click-to-Run installations, ODBC drivers are present but not registered in the usual locations, so 64-bit DSNs may not appear in ODBC Administrator. This is unexpected behavior of Office C2R builds.

Therefore, here are several suggestions that you can try in this case to see if they can help:

1.Confirm what you need:

• If you need full Access functionality (design tables, queries, forms), uninstall Access Runtime and keep the full Access app from Office 365.
• If you only need to run an Access-based app, Runtime is fine, but you must open an existing .accdb or .mdb file directly (double-click or use command line).

2.Remove the conflicts:

• Go to Control Panel > Programs and Features.
• Uninstall Microsoft Access Runtime.
• Repair Office 365 installation (via Apps & Features > Office > Modify > Quick Repair).

3.ODBC driver fix: if ODBC DSNs are missing, install the Access Database Engine Redistributable matching the bit of your Office (32-bit or 64-bit).

Reference: https://www.microsoft.com/en-us/download/details.aspx?id=54920

4.Additional practice:

• Do not mix 32-bit and 64-bit Office components. If Office is 64-bit, install 64-bit Access Runtime or Database Engine.
• For Click-to-Run installations, external apps cannot use Access ODBC/OLEDB unless the redistributable is installed. See more details in here: https://support.aggsoft.com/knowledgebase.php?article=93

Please note that our support is limited to providing guidance based on official Microsoft documentation. Any third-party resources or references shared are intended solely for informational or consultative purposes. Microsoft does not guarantee the accuracy, reliability, or continued availability of third-party content, and we recommend exercising discretion when referring to such materials. 

Lastly, I would like to remind a short experience in this case: the error occurs because Access Runtime was installed alongside Office 365, which forces Access to run in Runtime mode. If you need full Access, uninstall Runtime and repair Office. If you only need Runtime, open an existing Access file directly. For missing ODBC drivers, install the Access Database Engine Redistributable matching your Office bit.

I hope this information can give you more insights in this situation and please feel free to give any feedback in comment section. Wish you a pleasant day!

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