Why ActiveX Stops Working in Office 2024/Microsoft 365 and How to Diagnose It

1. What You Need to Know First

In Office 2024 and Microsoft 365, ActiveX controls are disabled by default. When Excel buttons and forms, or embedded objects in Word / PowerPoint, suddenly appear to “stop working” after an update, the cause is usually not a broken program but a change in security defaults.

The causes fall into three broad categories.

1. Security setting changes (Trust Center, ActiveX disabled by default)
2. 32-bit / 64-bit mismatch (loading a 32-bit-only control into 64-bit Office)
3. Missing COM registration or dependent DLLs / runtimes (regsvr32 never run, missing VC++ runtime)

Field rule of thumb: Working through these from the top, in this order, is the fastest path.

Terms Used in This Article

For IT administrators, here are the terms that appear later in the article without further explanation.

How This Article Is Organized

It is a long article, so read the parts you need. It falls into three large groupings.

If you are in a hurry, start with Chapter 11, “Common Symptoms and Remedies,” find your symptom there, and jump back to the Step it points to.

In the diagram a solid line marks a relation that always holds and a dashed line marks a conditional one (the conditions are given per relation on the detail page). The full list of relations (24 in total, with evidence and certainty) and the definitions of the main concepts are collected on the knowledge map detail page (in Japanese). Data: JSON-LD / Turtle

2. Office 2024 Family vs Microsoft 365 — What Is Different

Important: The registry path remains 16.0 even in Office 2024. Searching for 24.0 “because it says 2024” is a classic detour.

A Note on Windows 10

General support for Windows 10 ended on October 14, 2025. Microsoft 365 Apps, however, is in a migration grace period on Windows 10, with security updates provided until October 10, 2028. In other words, the situation looks like this:

• It is not the case that “nothing works at all on Windows 10”
• You are running under the dual premise of “OS out of support, Apps in a grace period”

3. Troubleshooting Overview

flowchart TD
    A[Reproduce the symptom] --> B[Collect Office product name, build, bitness, and OS information]
    B --> C{Are the OS / Office support prerequisites OK?}
    C -- No --> C1[Fix prerequisites: review OS / Office edition / channel]
    C -- Yes --> D[Check the Trust Center]
    D --> E{Problem with ActiveX settings / Protected View / Trusted Documents?}
    E -- Yes --> E1[Fix settings, signing, and distribution design]
    E -- No --> F{Depends on legacy Web / IE?}
    F -- Yes --> F1[Check IE mode and the site list]
    F -- No --> G[Check CLSID / InprocServer32 / TypeLib]
    G --> H{Is COM registration healthy?}
    H -- No --> H1[regsvr32 / RegAsm / reinstall]
    H -- Yes --> I[Check dependent DLLs / .NET / VC++ runtimes]
    I --> J{Are the dependencies satisfied?}
    J -- No --> J1[Repair and redistribute the relevant runtime]
    J -- Yes --> K[Collect logs / Procmon / Process Explorer]
    K --> L[Check build deltas and security update deltas]

4. Step 1 — Collect Environment Information

First, always record the following information. The point is to decide based on numbers, not on impressions.

On the Office side

• Check under [File] -> [Account] -> [Product Information]
  • Product name (Office 2024 vs Microsoft 365)
  • Version and build number (most important)
  • Installation type (Click-to-Run)
• Check 32-bit / 64-bit in the product information dialog under [About Excel] / [About Word], and so on

On the Windows side

# Basic OS information
Get-CimInstance Win32_OperatingSystem |
  Select-Object Caption, Version, BuildNumber, OSArchitecture

# Executable paths of Office processes
Get-Process WINWORD, EXCEL, POWERPNT, VISIO -ErrorAction SilentlyContinue |
  Select-Object ProcessName, Path

How to read the output

The output itself differs from machine to machine, so here are the columns to look at and how to judge them.

If Get-Process returns nothing at all, it only means the Office app in question is not running. Open the app you want to check and run the command again. Because -ErrorAction SilentlyContinue is specified, process names that are not running do not raise an error.

You can also read the Office bitness from the app’s own menus. In Excel, go to File -> Account -> About Excel, and the first line of the dialog that opens shows the version, the build number, and either “32-bit” or “64-bit” side by side. Copying that line down verbatim makes vendor inquiries and reproduction work go much faster.

Common pitfalls

5. Step 2 — Check the Trust Center and Security Settings

What you are doing here is separating “the file itself is being blocked” from “loading the COM component is failing.”

Checklist (in order, from the top)

Where to look on screen

Instead of screenshots, here is where each thing sits and in what order to click.

• Message bar: right after the file opens, it appears as a wide band between the ribbon and the editing area. If you dismissed it, close the file and reopen it to bring it back.
• ActiveX Settings screen: going to File -> Options -> Trust Center only gets you to a page of explanatory text and a button. The settings themselves live behind the “Trust Center Settings…” button, and in the dialog that opens you pick “ActiveX Settings” from the list on the left. Skip that one hop and you never reach the screen you are after. Microsoft’s own guidance also describes enabling ActiveX as this configuration change, not as a one-time allow from the message bar.
• Protected View / Trusted Documents / Trusted Publishers: all three sit in the same left-hand list inside the Trust Center Settings dialog. Clearing the trusted documents record before a reproduction attempt keeps machine-to-machine differences from creeping in.

Watch the scope of the setting: the ActiveX settings apply not only to the file you currently have open but to every Word / Excel / PowerPoint / Visio file. This is not an “allow this one file” setting. If you loosen it temporarily for an investigation, always put it back.

What to try first

1. Copy the problem file to a locally managed folder (for example C:\Temp) and save it under a different name
2. Avoid opening it directly from a network share or an email attachment (to rule out Protected View)
3. Start Office in safe mode to isolate the influence of add-ins

excel /safe
winword /safe
powerpnt /safe

6. Step 3 — Check Whether It Depends on IE Mode

Sometimes what looks like an “ordinary ActiveX failure” turns out to be Edge’s IE mode not being configured.

• IE mode is not a browser-wide switch. It applies only to the sites registered in the Enterprise Site List
• If only part of your internal web integration fails, check whether that site is actually covered by IE mode

Here is where to look:

• Edge policies: Administrative Templates > Microsoft Edge
• Registry: HKLM\SOFTWARE\Policies\Microsoft\Edge
• Diagnostics page: edge://compat/iediagnostic

7. Step 4 — Check COM Registration

If the Trust Center is clean, the next thing to verify is whether the COM component itself is registered correctly.

Basic verification commands

:: Check CLSID registration status
reg query "HKLM\SOFTWARE\Classes\CLSID\{YOUR-CLSID-HERE}\InprocServer32" /s

:: Register / unregister a native COM / ActiveX DLL
regsvr32 C:\Path\YourControl.dll
regsvr32 /u C:\Path\YourControl.dll

How to read the result

There are three things to look at in the reg query output.

1. Whether the key exists. If it does not, nothing is printed and you get only a “not found” error. That alone settles it: the component is not registered.
2. The DLL path stored in the default value. That path is the COM component itself.
3. Whether a file actually exists at that path. It is common for an uninstall or a file move to remove the binary while leaving the registration behind.

If you want the check and the verdict in one go, PowerShell reads better.

# Replace with the CLSID you want to inspect (include the braces)
$clsid = '{00000000-0000-0000-0000-000000000000}'
$key   = "HKLM:\SOFTWARE\Classes\CLSID\$clsid\InprocServer32"

if (Test-Path $key) {
  $server = Get-ItemPropertyValue -Path $key -Name '(default)'
  [pscustomobject]@{
    CLSID      = $clsid
    Server     = $server
    FileExists = Test-Path $server
  }
} else {
  Write-Host "Not registered: $key was not found"
}

If FileExists is False, the registration survives but the binary is gone. You need a reinstall or a re-registration.

Look in the right place: when you register a 32-bit COM component on 64-bit Windows, the entries land under HKLM\SOFTWARE\Classes\WOW6432Node\CLSID\{CLSID} instead. Looking only at HKLM\SOFTWARE\Classes\CLSID from 64-bit PowerShell or reg query makes it look unregistered, so when troubleshooting 32-bit Office, always check under WOW6432Node as well.

For COM components built with .NET (important)

regsvr32 cannot be used on .NET assemblies. Use RegAsm.

:: 32bit Office on 64bit Windows -> use the Framework RegAsm
"C:\Windows\Microsoft.NET\Framework\v4.0.30319\RegAsm.exe" "C:\Path\YourControl.dll" /codebase /tlb

:: 64bit Office -> use the Framework64 RegAsm
"C:\Windows\Microsoft.NET\Framework64\v4.0.30319\RegAsm.exe" "C:\Path\YourControl.dll" /codebase /tlb

A classic way this breaks: “the RegAsm bitness does not match the Office bitness” -> registration succeeds in the registry, but Office cannot find the component.

8. Step 5 — Check Dependent DLLs and Runtimes

When “the main DLL is there but it will not load,” the usual explanation is a missing dependency.

Runtimes that go missing most often in the field

Low-level investigation tools

Capture a Procmon log while the problem reproduces and filter on NAME NOT FOUND, and you can see at a glance which DLL or registry key could not be found.

How to set up the filters, how to strip out the noise, and which events to read first are written up as a procedure in A Practical Guide to Process Monitor (ProcMon). And if the combination of registration and bitness is what has you stuck, Registration and Bitness Pitfalls in COM/OCX/ActiveX Development covers the same problem from the developer’s side.

9. Step 6 — Capture Logs for the Final Check

If the cause is still unidentified at this point, turn logging on and catch the moment it reproduces.

Enable general Office logging

reg add HKCU\Software\Microsoft\Office\16.0\Common\Logging /v EnableLogging /t REG_DWORD /d 1

Enable detailed Click-to-Run logging

reg add HKLM\SOFTWARE\Microsoft\ClickToRun\OverRide /v LogLevel /t REG_DWORD /d 3
reg add HKLM\SOFTWARE\Microsoft\ClickToRun\OverRide /v PipelineLogging /t REG_DWORD /d 1

Logs are written to %windir%\temp or %temp%.

Use Event Viewer alongside

eventvwr.msc

• Check Windows Logs > Application
• .NET Runtime and SideBySide errors are often the decisive clue

Turn logging back off after the investigation (don’t forget)

reg delete HKCU\Software\Microsoft\Office\16.0\Common\Logging /v EnableLogging /f
reg delete HKLM\SOFTWARE\Microsoft\ClickToRun\OverRide /v PipelineLogging /f
reg delete HKLM\SOFTWARE\Microsoft\ClickToRun\OverRide /v LogLevel /f

10. Key Registry / Policy Quick Reference

Four paths worth memorizing

With 32-bit Office on 64-bit Windows, check under Wow6432Node as well for anything COM-related.

Frequently used test registry entries (verification only)

Windows Registry Editor Version 5.00

; Test only: lift the blanket ActiveX disable
[HKEY_CURRENT_USER\Software\Microsoft\Office\Common\Security]
"DisableAllActiveX"=dword:00000000

Warning: these settings are for verification only. Handle the permanent fix through “a trusted distribution path plus signing.”

11. Common Symptoms and Remedies

12. Recommended Settings for Enterprises

The basis of a permanent fix is not “lower security across the board” but “allow only what is needed, narrowly.”

Example Microsoft 365 deployment configuration (32-bit + Monthly Enterprise)

<Configuration>
  <Add OfficeClientEdition="32" Channel="MonthlyEnterprise">
    <Product ID="O365ProPlusRetail">
      <Language ID="ja-jp" />
    </Product>
  </Add>
  <Updates Enabled="TRUE" />
  <Display Level="None" AcceptEULA="TRUE" />
</Configuration>

13. Last Resort — Repair

• Quick Repair / Online Repair is effective against broken settings and broken registration
• It does not, however, solve x86 / x64 mismatches or signing / policy problems themselves
• Repair goes last (running it first contaminates your investigation logs)

14. Command Quick Reference

15. Conclusion — Don’t Get the Order Wrong

misconfiguration -> OS / bitness mismatch -> COM component problem -> dependencies -> update deltas

Even when an ActiveX problem looks like “just an Excel issue,” it is really a problem where five layers intersect: Office’s default security + the Windows support prerequisites + COM component registration + dependent runtimes + the update model. Rather than loosening settings at random, isolate from the top down and you will land on a repair that is far less likely to come back.

Reference Links

• ActiveX controls are disabled by default in Microsoft 365 and Office 2024 — scope of impact of the default disablement
• Enable or disable ActiveX settings in Office files — the resource closest to user operations
• Update history for Office LTSC 2024 and Office 2024 — build comparisons, pre/post-update deltas
• Overview of update channels for Microsoft 365 Apps — differences between Current / Monthly Enterprise / Semi-Annual
• Release Information for Updates to Microsoft 365 Apps — channel-driven behavioral differences
• Compatibility between the 32-bit and 64-bit versions of Office — decision criteria when ActiveX / COM assets are involved
• Internet Explorer mode in Microsoft Edge — Enterprise Site List and policies
• regsvr32 command — registering / unregistering native COM
• Regasm.exe (Assembly Registration Tool) — registering COM components built with .NET
• Process Monitor (Procmon) — tracking NAME NOT FOUND / PATH NOT FOUND
• Process Explorer — DLL load status of a process
• Latest supported Visual C++ Redistributable Downloads — where to check for missing VC++ runtimes
• .NET Framework installation guide — checking .NET Framework versions

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Frequently Asked Questions

Common questions about the topic of this article.

What does it mean that ActiveX is disabled by default in Office 2024 and Microsoft 365?

In Office 2024 and Microsoft 365, ActiveX controls are disabled by default. When Excel buttons and forms, or embedded objects in Word / PowerPoint, that used to work suddenly appear to stop working after an update, the cause is usually not a broken program but this change in security defaults. The first step is to choose Enable Content on the yellow message bar that appears when you open the file, see whether the control works temporarily, and then check the ActiveX Settings in the Trust Center.

An ActiveX button in Excel stopped responding after an Office update. What should I check first?

The causes fall into three broad categories. First, a change in security settings (Trust Center, ActiveX disabled by default, Protected View). Second, a 32-bit / 64-bit mismatch (a 32-bit-only control loaded into 64-bit Office). Third, missing COM registration or missing dependent DLLs / runtimes (regsvr32 never run, VC++ runtime absent). Working through these from the top, in that order, is the shortest path. Along with that, record the product name, build number, Office bitness, and OS information up front, and compare behavior from a local folder instead of opening the file directly from a network share or an email attachment.

Why does an ActiveX control fail only on 64-bit Office?

Because the bitness of Office and the bitness of the COM / ActiveX component have to match. A 32-bit-only control will not run in 64-bit Office. Ask the vendor whether an x64 build exists, and if there is none, consider switching to 32-bit Office. For COM components built with .NET, use RegAsm rather than regsvr32: the Framework RegAsm for 32-bit Office and the Framework64 RegAsm for 64-bit Office. When the RegAsm bitness does not line up with Office, you hit the classic failure where registration succeeds in the registry but Office still cannot find the component.

How should I configure things so that ActiveX works permanently?

The principle is to allow only what is needed, narrowly, rather than lowering security across the board. Changing the DisableAllActiveX registry value is strictly for verification; the permanent fix comes from a trusted distribution path plus signing. Concretely, code-sign the ActiveX controls, macros, and add-ins you distribute internally and manage Trusted Publishers centrally, consider the Monthly Enterprise Channel on Microsoft 365 because its changes are easier to track, and give priority consideration to 32-bit Office unless the vendor explicitly states x64 support. Before rolling out to production, build a pilot ring and validate against a fixed build on representative documents and representative machines.

Author Profile

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Go Komura

Representative of KomuraSoft LLC

Focused on Windows software development, technical consulting, and investigations into failures that are difficult to reproduce.