How to Fix Access Custom Ribbon XML Error 0x80004005
Question details
The user needs to resolve an error that occurs when reopening an Access database with a custom ribbon stored in the usysRibbons table.
- Product
- Microsoft Access
- Device & OS
- not provided
- Scenario
- Loading a custom ribbon UI from the usysRibbons table upon opening a database.
- Observed behavior
- An 'unknown namespace or missing DTD and schema declaration' error (0x80004005) appears, preventing the custom ribbon from loading correctly.
Before editing your system tables, create a backup copy of your Access database file (.accdb) to prevent accidental data loss while modifying the XML schema.
Correct the Namespace URL in the Ribbon XML
The most common cause of Error 0x80004005 is a typographical error, such as a trailing space, in the customUI namespace declaration.
Access strictly parses the XML for custom ribbons. Any hidden characters or extra spaces in the namespace URL will cause the parsing to fail and trigger an 'unknown namespace' error.
Open your Access database, enable the viewing of system objects in the Navigation Pane options, and open the usysRibbons table where your custom XML is stored.
Find the row for the specific ribbon causing the error and click into its RibbonXML field.
Carefully check the <customUI> tag's xmlns attribute URL. Ensure it matches the exact Microsoft schema URL without any deviations.
Delete any trailing spaces, especially immediately after the '.com' portion of the namespace URL, and save the changes to the table.
Close the database completely and reopen it to verify that the custom ribbon now loads without the 0x80004005 error.
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Frequently Asked Questions
Does Access have a built-in XML editor for custom ribbons?
No, Microsoft Access does not include a built-in ribbon designer or XML editor. You must write the XML in a text editor or use third-party tools like Ribbon Creator before pasting it into the usysRibbons table.
Why did my built-in ribbon disappear when using the Access Runtime version?
The Access Runtime environment automatically hides the built-in ribbon. This is the intended normal behavior to prevent end-users from modifying database designs. You must build and load a custom ribbon if you want users to have navigation controls.
Where can I find the correct idMso values for Access ribbon controls?
You can download the Office Fluent User Interface Control Identifiers from the official Microsoft Download Center. These files provide comprehensive lists of idMso values for all Office applications, including Access.
Can I customize the default Access ribbon without writing XML?
You can make basic customizations for your local application by going to File > Options > Customize Ribbon. However, to deploy a custom ribbon embedded within a specific database file for all users, you must use XML in the usysRibbons table.
