Skip to main content
Grunt is moving from the .NET Framework 4.7.2 VSTO add-in to a .NET 9 native COM add-in. The migration begins in 2026.2 and 2026.3 will be .NET 9 only. This page covers what IT administrators need to know to prepare.

​
Migration timeline

ReleaseWhat happens
2026.2.NET 9 COM add-in ships alongside the existing .NET Framework version. Organizations can begin testing and migrating.
2026.3.NET 9 only. The .NET Framework 4.7.2 VSTO add-in is retired.

​
What changes

AreaCurrent (.NET Framework 4.7.2)New (.NET 9, from 2026.2)
Add-in typeVSTO add-inCOM add-in
Runtime dependencies.NET Framework 4.7.2 + VSTO RuntimeSelf-contained (no external runtime)
Primary binaryAltua.Grunt.PowerPoint.dll + .vsto manifestGrunt.PowerPoint.ComAddinNE.dll
Architecturex64 and x86x64 and arm64
Add-in ProgIDGruntGrunt
Add-in FriendlyNameGruntGrunt

​
Runtime prerequisites removed

The current version requires the VSTO Runtime and .NET Framework 4.7.2 on each machine. The .NET 9 release is self-contained — the .NET 9 runtime is bundled inside the installer. No separate runtime installation will be needed. Once you have migrated to the .NET 9 version, the VSTO Runtime and .NET Framework prerequisite steps in your deployment process can be removed.

​
Registry changes

​
Add-in registration

The PowerPoint add-in registration path will remain the same: 
Software\Microsoft\Office\PowerPoint\AddIns\Grunt
However, some keys will change:
KeyCurrent valueNew value (.NET 9)
FriendlyNameGruntGrunt
DescriptionData bindinggrunt.pro
LoadBehavior33
Manifest<path>\Altua.Grunt.PowerPoint.vsto|vstolocal(removed)
The Manifest key points to the VSTO manifest and will no longer be used. The COM add-in is located through CLSID registration instead.

​
VSTO security entries removed

The current version writes VSTO trust entries under: 
Software\Microsoft\VSTO\Security\Inclusion\{3c27e410-2cf0-479b-b8ff-fce807e39615}
These entries will no longer be created by the .NET 9 version. If you have Group Policy or scripts that manage VSTO trust entries for Grunt, they can be retired after the migration.

​
COM class registration added

The .NET 9 version registers a COM class so PowerPoint can load the add-in: 
Software\Classes\CLSID\{AAF65EB4-AFBA-4B65-98AD-381C670B6461}
Software\Classes\CLSID\{AAF65EB4-AFBA-4B65-98AD-381C670B6461}\InprocServer32
Software\Classes\CLSID\{AAF65EB4-AFBA-4B65-98AD-381C670B6461}\ProgID
Software\Classes\Grunt
Software\Classes\Grunt\CLSID
These will be created automatically by the MSI installer.

​
Grunt metadata key added

A new registry key will store add-in metadata: 
Software\Grunt
    architecture = <x64 or arm64>
    Version      = <semantic version>
    Revision     = <revision identifier>
    content      = <content directory path>
    variant      = <variant>
    ClientId     = <client identifier>

​
VSTO trust manager fix no longer needed

The current VSTO version sometimes requires a registry fix at: 
HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\.NETFramework\Security\TrustManager\PromptingLevel
This will no longer be relevant after the migration. If your deployment includes this fix specifically for Grunt, it can be removed once you are on the .NET 9 version.

​
32-bit support dropped

The current version ships both x64 and x86 installers. The .NET 9 version will ship x64 and arm64 only. Organizations still running 32-bit Office should upgrade to 64-bit Office before deploying the .NET 9 version.

​
Upgrade path

The MSI installer will handle the upgrade in place. No manual uninstall of the previous version is needed — the installer detects the existing installation and upgrades it. For managed deployments:
  1. Download the .NET 9 MSI from app.grunt.pro/download once it is available in 2026.2.
  2. Deploy it through your existing software distribution tooling (Intune, SCCM, etc.) using the same flags as before.
  3. The installer will remove the old VSTO-based version and install the new COM add-in.
  4. Validate by opening PowerPoint and confirming the Grunt tab appears.
For per-user installs, auto-update will handle the upgrade automatically if enabled.

​
Endpoint protection

After migrating, if your endpoint protection allowlist references the old binary name (Altua.Grunt.PowerPoint.dll), update it to the new binary:
  • Grunt.PowerPoint.ComAddinNE.dll
See Network and security for the full list of paths.

​
COM add-in policy

If your organization uses Office Group Policy to manage COM add-ins, ensure the Grunt ProgID (Grunt) or CLSID ({AAF65EB4-AFBA-4B65-98AD-381C670B6461}) is allowed. The current VSTO-based add-in does not require COM add-in policy configuration, but the .NET 9 COM add-in will.