Disable Smart Document's use of manifests
This user-scoped policy controls whether Word and Excel can load XML expansion pack manifest files for Smart Documents.
since 0.9.8.11
Purpose
Show registry keys (1)
HKCU\software\policies\microsoft\office\common\smart tag\neverloadmanifests
This user-scoped policy controls whether Word and Excel can load XML expansion pack manifest files for Smart Documents.
An XML expansion pack can contain XML schemas, XSLT files, DLLs, images, and additional document or data files. Its manifest identifies the components and their locations and provides information Office uses to set up the Smart Document solution.
neverloadmanifests is a REG_DWORD value. A value of 1 prevents Office from loading these manifests. A value of 0, or the absence of the policy value, permits manifest loading.
Notes
Security
A manifest can instruct Office to set up components supplied by an XML expansion pack. These components can include executable elements such as COM objects that require installation or registration. Blocking manifests removes this deployment and loading path for Smart Document solutions, reducing exposure to untrusted expansion packs.
This policy does not completely disable the Smart Documents feature. Its specific effect is to prevent the associated manifest files from being loaded.
Possible side effects
Smart Document solutions that rely on a manifest to load or set up their XML expansion pack no longer work as designed. Their application logic, schemas, transformations, controls, or other package components can consequently become unavailable.
Notes
The setting applies to the current user. It is included in the shared Office 16 administrative templates that Microsoft provides for products including Microsoft 365 Apps, Office LTSC, and Office 2016.
Microsoft documentation
Microsoft Download Center: Administrative Template files (ADMX/ADML) for Microsoft Office
Microsoft Learn: XmlNamespaces.InstallManifest method (Excel)