Empty Vault tab in AutoCAD: the tab is there, but no buttons

On a workstation running AutoCAD Mechanical 2025 with the Vault 2025 client, the Vault add-in appears to load correctly: the Vault tab shows up in the ribbon, the panels too… but they are empty. Not a single button. No way to check files in or out from AutoCAD.

No error message, nothing on the command line. The add-in looks half loaded.

How the Vault ribbon is built

To understand the symptom, you have to look at the bundle's PackageContents.xml:

<ComponentEntry AppName="Vault Plugin Partial Menu"
                ModuleName="./Contents/VaAc.cuix"
                LoadOnAutoCADStartup="True">
  <RibbonControls>
    <RibbonControl Name="Vaac"
        Path="pack://application:,,,/vaac_startupUIMgd;component/VaacControls.xaml"/>
  </RibbonControls>
  <AssemblyMappings>
    <AssemblyMapping Name="vaac_startupUIMgd"
        Path="./Contents/vaac_startupUIMgd.dll"/>
  </AssemblyMappings>
</ComponentEntry>

The Vault ribbon is built in two steps:

• the CUIx file defines the tab and the panels. A CUIx is not tied to an AutoCAD release: it always loads;
• the buttons are WPF controls loaded from the vaac_startupUIMgd.dll assembly through the pack URI pack://application:,,,/vaac_startupUIMgd;component/VaacControls.xaml.

A tab and panels that are present but empty therefore mean the CUIx loaded, while loading vaac_startupUIMgd.dll failed — silently.

The real cause

Listing the bundles installed on the machine, one folder stands out: VaultAutoCAD2027.bundle, installed with the Vault 2027 client beta. Its PackageContents.xml declares:

<RuntimeRequirements OS="Win64" Platform="AutoCAD|ADT|Civil3D|..."
                     SeriesMin="R25.0" SeriesMax="R32.0" ... />

SeriesMin="R25.0": this bundle declares itself compatible with AutoCAD 2025, while its binaries (version 32.0.71.0) are built for AutoCAD 2027 (R26.0). By comparison, the Vault 2026 bundle is correctly bounded with SeriesMin="R25.1" SeriesMax="R25.1".

And that's not all: the Vault 2025 and 2027 bundles share the same ProductCode. To the AutoCAD autoloader, they are the same application installed in two versions, and the one with the highest AppVersion wins: 32.0.0.0 versus 30.0.0.0.

The result in AutoCAD Mechanical 2025:

1. the autoloader picks the Vault 2027 bundle;
2. its CUIx loads without a hitch → the tab and panels show up;
3. its version 32 vaac_startupUIMgd.dll, built against the AutoCAD 2027 assemblies, fails to load → no buttons;
4. no error is ever reported to the user.

The same flaw also breaks the Vault add-in in AutoCAD 2026, whose R25.1 series falls within the faulty range as well.

The fix

Simply correct SeriesMin in the 2027 bundle's PackageContents.xml so it only loads in AutoCAD 2027. In an elevated PowerShell console:

$file = 'C:\Program Files\Autodesk\ApplicationPlugins\VaultAutoCAD2027.bundle\PackageContents.xml'
Copy-Item $file "$file.bak"
(Get-Content $file -Raw) -replace 'SeriesMin="R25\.0"', 'SeriesMin="R26.0"' |
    Set-Content $file -Encoding utf8BOM

After restarting AutoCAD Mechanical 2025, the autoloader only keeps the Vault 2025 bundle: the Vault tab gets its buttons back.

One last word of caution: an update of the Vault 2027 beta client may rewrite this file with the faulty range. If the Vault tab ever goes empty again, this is the first place to check.