Regression: Outlook no longer renders embedded OLE/VML Macrobond chart preview using EMZ image data

Preface:

This is an AI-assisted diagnosis, manually directed and reviewed by the reporting user. The conclusion is based on inspection of the email HTML source and the embedded metafile structure.

Product:

Microsoft Outlook for Windows (both Classic and New)

Issue:

After a recent Outlook update, Macrobond charts embedded in emails no longer render visibly in the inbox/reading pane. The same email content previously rendered correctly.

Observed behaviour:

The email contains an embedded Office/OLE chart object with a visual preview. In previous Outlook builds, this rendered as an inline chart image. In the latest Outlook version, the chart area no longer displays correctly.

Relevant email-source structure:

The object is represented as an Office/VML/OLE object with an EMZ preview and a PNG fallback:

<v:shape id="_x0000_i1031" type="#_x0000_t75"

style='width:386.1pt;height:249.3pt' o:ole="">

<v:imagedata src="cid:image001.emz@01DCB2F1.27E7FE10" o:title="" />

</v:shape>

<img width=515 height=332

src="cid:image002.png@01DCB2F1.27E7FE10"

v:shapes="_x0000_i1031">

<o:OLEObject Type="Embed"

ProgID="Mbnd.mbnd"

ShapeID="_x0000_i1031"

DrawAspect="Content"

ObjectID="_1834915328">

</o:OLEObject>

Analysis:

The Office/VML path appears to use cid:image001.emz as the display preview for an OLE-backed shape. The ProgID="Mbnd.mbnd" identifies the embedded object as a Macrobond object. The PNG appears only as a non-VML fallback.

The likely regression is that Outlook is still selecting the MSO/VML/OLE rendering path, but no longer renders the EMZ preview correctly. Because the PNG fallback is inside the non-VML branch, Outlook may not fall back to it when the VML branch fails.

Expected behaviour:

Outlook should either:

1. continue rendering the EMZ preview for OLE-backed VML shapes as before; or
2. fall back to the available PNG representation when the EMZ/OLE/VML preview cannot be rendered.

Actual behaviour:

The embedded chart does not render visibly, despite the email containing both an EMZ preview and a PNG fallback.

Impact:

This breaks existing workflows where Macrobond charts are embedded in Outlook emails and expected to be both visible in the reading pane and openable/editable via the associated OLE object.

Requested investigation:

Please investigate whether a recent Outlook update changed handling of:

• v:shape elements with o:ole="";
• v:imagedata pointing to cid: EMZ content;
• OLE-backed Office objects with ProgID="Mbnd.mbnd";
• fallback selection where the VML branch exists but its preview fails to render.

Attachments/evidence available:

A sample email source and extracted metafile can be provided on request.