After installing Windows Update KB5094126 (June 2026) , our application fails when opening Word via COM automation. Error: HRESULT 0x80020005 (DISP_E_TYPEMISMATCH) Type mismatch Happens during Documents.Open() (IDispatch call) Fully reproducible Works again after uninstalling KB5094126 Impact: Breaks Word integration / reporting completely Affects multiple environments Tested with: Word 2013 Word 2021 Microsoft 365 → So not Office-specific, likely COM/Windows layer Question: Has anyone seen this after KB5094126? Was there a change in COM/OLE automation or VARIANT handling in this update?

Fixed by Microsoft for Windows 11 with a new patch July 14, 2026—KB5101650 (OS Builds 26200.8875 and 26100.8875) for Windows 10 with a new patch July 14, 2026—KB5099539 (OS Builds 19045.7548 and 19044.7548) For all OS see following table OS Resolving KB Windows 11 26H1 KB5101649 Windows 11 25H2 / Windows 11 24H2 KB5101650 Windows 11 23H2 KB5099414 Windows Server 2025 KB5099536 Windows 10 ESU KB5099539 Windows Server 2022 KB5099540 Windows Server 2019 KB5099538 Windows Server 2016 KB5099535 Windows Server 2012 R2 KB5099444

one annotation: we were fine for generating one document in a loop after that we had the same error typeconflict after research we found out that Table generation did the problem oTables.Add() was fault, we had as last parameter vtOptional for autoformation , but it want's a true or false !!!!!!! bmks=oDoc.GetBookmarks(); bmk=bmks.Item(COleVariant("Tabelle_01")); oRange = bmk.GetRange(); oTables = oDoc.GetTables(); if (anzahl>0) { oTable = oTables.Add(oRange,(long) anzahl,(long) 5,vtOptional**,vtTrue); //** oBorders = oTable.GetBorders(); ]

After installation of KB5094126 the Word integration over COM fails

Daratha, Paul 95

After installing Windows Update KB5094126 (June 2026), our application fails when opening Word via COM automation.

Error:

HRESULT 0x80020005 (DISP_E_TYPEMISMATCH)
Type mismatch

Happens during Documents.Open() (IDispatch call)
Fully reproducible
Works again after uninstalling KB5094126

Impact:

Breaks Word integration / reporting completely
Affects multiple environments

Tested with:

Word 2013
Word 2021
Microsoft 365

→ So not Office-specific, likely COM/Windows layer

Question: Has anyone seen this after KB5094126? Was there a change in COM/OLE automation or VARIANT handling in this update?

Daratha, Paul 95 Reputation points

2026-06-11T19:00:40.4933333+00:00
Other sources complains about same problem. See

https://www.reddit.com/r/sysadmin/comments/1u31bje/kb5094126_breaking_word_integration_with_some/?rdt=38900

https://forums.zotero.org/discussion/132111/word-for-windows-zotero-experienced-an-error-updating-your-document
Viorel 127.3K Reputation points

2026-06-11T19:05:54.51+00:00

Which code has to be changed?
Leigh Menzel 10 Reputation points

2026-06-11T21:19:51.19+00:00

Yes, we are having the exact same issue with our software. I am looking for a solution now but was thinking I might update our Word and Excel reporting to a later version. You mentioning that it is also happening with Word 2021 and Office 365 is a huge help, thanks. I won't bother with that step for now then.
Lahinirina, Eric 15 Reputation points

2026-06-12T10:15:01.58+00:00

We are having the exact same issues. We are using Word COM automation with C++/MFC. And what we see so far is that calling a Word object method through a COleDispatchDriver inherited class crashes if you provide an optionnal parameter with COleVariant vtMissing((long)DISP_E_PARAMNOTFOUND, VT_ERROR);

This issue is quicky affecting all of our customers worldwide.
Leandro Rodrigues 5 Reputation points

2026-06-12T14:54:25.5366667+00:00

I've had the same issue with the OLE automation, solved after the hotfix removal.
Alan Reagan 16 Reputation points

2026-06-12T17:18:32.7333333+00:00

A vendor with affected software is attributing it to changes to Virtualization‑Based Security (VBS), Hypervisor‑Enforced Code Integrity (HVCI), and updated code integrity baselines. KB5094126 covers critical vulnerabilities. This needs to be fixed with Known Issue Rollback so KB5094126 doesn't have to be removed.
Koby Roberts 0 Reputation points

2026-06-16T01:02:30.42+00:00

I was able to use the Open method. However, I had to go straight IDispatch. I have to go around the MFC Wrappers.
Justin 30 Reputation points

2026-06-16T14:43:17.18+00:00

@Jürgen Hillmann

Nice to hear!!

I'm from Germany... ;-)
Jürgen Hillmann 5 Reputation points

2026-06-16T14:45:37.0266667+00:00

oh cool , i am also from Germany -

die Deutschen sind doch nicht so schlecht ! :-)
Jürgen Hillmann 5 Reputation points

2026-06-16T14:46:28.0666667+00:00

@Justin hope MS is not changing this behaviour anymore !!!!!
Houmard Matthias 0 Reputation points

2026-06-17T07:54:08.12+00:00

Following the installation of KB5094126, not only was the data transfer process in Word blocked, but the OLE or COM data transfer process in Excel was also blocked by third-party software. Interestingly, in Excel, the table was created in each instance, the header rows were visible and correct, but the table was not populated with content.
ChuckieAJ 411 Reputation points

2026-06-24T16:40:08.1666667+00:00

I am experiencing this now too with Word automation, including my userbase.
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Answer accepted by question author

Homero Junior 80

My integration had been having issues ever since the update that broke it. All it took was installing this update—KB5101650—and everything started working again. Just install update KB5101650, restart, and you're all set.

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11 additional answers

Daratha, Paul 95

Fixed by Microsoft

for Windows 11 with a new patch July 14, 2026—KB5101650 (OS Builds 26200.8875 and 26100.8875)
for Windows 10 with a new patch July 14, 2026—KB5099539 (OS Builds 19045.7548 and 19044.7548)

For all OS see following table

OS	Resolving KB
Windows 11 26H1	KB5101649
Windows 11 25H2 / Windows 11 24H2	KB5101650
Windows 11 23H2	KB5099414
Windows Server 2025	KB5099536
Windows 10 ESU	KB5099539
Windows Server 2022	KB5099540
Windows Server 2019	KB5099538
Windows Server 2016	KB5099535
Windows Server 2012 R2	KB5099444

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Homero Junior 80 Reputation points

2026-07-14T20:04:14.0366667+00:00

My integration had been having issues ever since the update that broke it. All it took was installing this update—KB5101650—and everything started working again. Just install update KB5101650, restart, and you're all set.
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Jürgen Hillmann 5 Reputation points

2026-06-20T05:03:26.76+00:00
one annotation:

we were fine for generating one document in a loop after that we had the same error typeconflict

after research we found out that Table generation did the problem

oTables.Add() was fault, we had as last parameter vtOptional for autoformation , but it want's a true or false !!!!!!!

bmks=oDoc.GetBookmarks();

bmk=bmks.Item(COleVariant("Tabelle_01"));

oRange = bmk.GetRange();

oTables = oDoc.GetTables();

if (anzahl>0)

{
```
			oTable =  oTables.Add(oRange,(long) anzahl,(long) 5,vtOptional**,vtTrue);  //** 

			oBorders = oTable.GetBorders();
```
]
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After installation of KB5094126 the Word integration over COM fails

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