Security Policy Errors

How to Fix Access Digital Signature Error During Database Migration

Adam Davis Sep 27, 2026 870 views

Question details

The user is experiencing security blocks when attempting to migrate or open ACCDB or ACCDE files due to missing or invalidated trusted digital signatures.

How to Fix Access Digital Signature Error During Database Migration

Product: Microsoft Access
Device & OS: not provided
Scenario: Migrating or deploying a Microsoft Access database (ACCDB/ACCDE) to another computer.
Observed behavior: Microsoft Access blocks the file from opening, displaying a security error regarding an untrusted or missing digital signature.

Before you start

Ensure you have administrative privileges on your computer to modify Microsoft Access Trusted Locations and verify that you have access to the original, uncompiled ACCDB file.

Solution 1Recommended

Apply Proper Signing Sequence for ACCDE Files

Follow the correct sequence of locking the VBA project and signing the ACCDB file before compiling it into an ACCDE file.

Compiling an ACCDB into an ACCDE file modifies the database structure. If the database is signed after changes are made, or if the VBA project isn't locked prior to compilation, the signature becomes invalid.

Open the Original Database

Open the original, working ACCDB file in Microsoft Access.

Lock the VBA Project

Press ALT + F11 to open the VBA Editor. Go to Tools > [Project Name] Properties, navigate to the Protection tab, and check 'Lock project for viewing'.

Sign the Database

Apply your digital signature to the VBA project by navigating to Tools > Digital Signature in the VBA Editor and selecting your certificate.

Compile the ACCDE File

Save your changes, return to the main Access window, and publish the database as an ACCDE file using File > Save As > Make ACCDE.

Apply Proper Signing Sequence for ACCDE Files

Best Practice: Always keep a backup of the original ACCDB file before creating an ACCDE file, as ACCDE files cannot be edited or modified.

Solution 2

Use a Signed ACCDC Package and Trusted Locations

If the application modifies the database and invalidates the signature, package it as an ACCDC file and extract it to a Trusted Location.

Solution 3

Verify IT Security Policies

Confirm that strict organizational IT policies are not overriding local trust settings or blocking your digital signature.

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Frequently Asked Questions

Why does my digital signature become invalid after compiling to ACCDE?

What is an ACCDC file and when should I use it?

An ACCDC file is an Access Deployment File. It packages and digitally signs your database, allowing you to deploy it securely. It is best used when your application modifies the database dynamically, which would otherwise invalidate a standard digital signature.

How do I add a Trusted Location in Microsoft Access?

Go to File > Options > Trust Center, click Trust Center Settings, select Trusted Locations, and click 'Add new location'. Browse to your desired folder, check the box to trust subfolders if necessary, and click OK.

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