Excel Error 0xc0000428: Causes, Meaning, and Safe Fixes

Excel error 0xc0000428 is usually a Windows code-integrity error: Windows cannot verify the digital signature or integrity of a file that Excel needs to start. Find the exact file named in the message, then repair or update the affected Office or Windows component; do not bypass signature checks or download replacement DLL files from unofficial sites.

What error 0xc0000428 means

The code is a Windows status value commonly identified as STATUS_INVALID_IMAGE_HASH. In practical terms, Windows has rejected an executable file or a library because its signature or integrity could not be validated under the checks currently in force. The file named in the error matters: it might be Excel itself, an Office component, or a DLL loaded by Excel, such as one supplied by an add-in.

This is not an Excel formula error, a workbook calculation result, or a message that explains a problem with a particular cell. It occurs at the Windows application-loading or security-check level. Excel may therefore fail before its normal window appears, or it may start and then report the problem when a component loads.

The same status can appear outside Excel, including during Windows startup if a Windows boot file is involved. If the message appears before you reach the desktop, treat it as a Windows startup problem rather than assuming that reinstalling Office will help. The file path and the point at which the message appears are useful clues.

Why Excel might trigger the message

Windows verifies files to help prevent altered or untrusted code from running. A failed check does not, by itself, prove that a file is malicious. It means Windows could not establish that the file meets the applicable integrity requirements. Common possibilities include:

Damaged Office files: an interrupted update, storage problem, or other corruption may leave an executable or library incomplete or inconsistent.
An add-in or integration: a third-party Excel add-in, document-management tool, antivirus integration, or other software may load a file Windows rejects.
Out-of-date software: an Office or Windows build may have a compatibility issue that a later update corrects.
Security or management policy: a work or school device may use application-control rules that block a file. Do not try to circumvent those rules; contact the organization’s IT administrator.
File alteration: an unofficial patch, modified executable, or unsafe download can invalidate trust. Malware is another possibility, but the code alone does not diagnose an infection.

A certificate or signature problem is not automatically proof that a publisher is untrustworthy. Likewise, a familiar filename is not proof that the file is genuine: malware can use convincing names. Verify the path and publisher rather than judging by the filename alone.

Identify the file and when the error occurs

Before changing settings, copy the full message and note the file path if Windows displays one. Record whether the error appears when launching Excel, opening a specific workbook, or starting Windows. If the dialog names a DLL rather than EXCEL.EXE, that distinction can point toward an add-in or another component.

Excel is commonly installed under a Microsoft Office folder in Program Files, but the exact location varies with the Office edition and installation. Do not assume that a file is safe merely because it is named EXCEL.EXE. In File Explorer, right-click the named file, select Properties, and, if available, inspect the Digital Signatures tab. Check that the signer is the expected publisher and that Windows reports the signature as valid. A missing tab is not conclusive on its own; file type and Windows display behavior can differ.

If the error names a file in an unfamiliar temporary folder or a location unrelated to the expected application, avoid opening it or approving prompts for it. On a managed PC, capture a screenshot and give the path and message to IT. If Windows Security reports a threat, review its details rather than restoring or allowing the file just to make Excel open.

Try the safest fixes first

Start with changes that restore supported software rather than weakening Windows security. Save open work, restart the PC, and install available Windows and Microsoft 365 updates through the normal update channels. A restart can complete an update that was waiting for a reboot, while current Office and Windows files may resolve a compatibility or corruption issue.

Next, repair Office. In Windows 11, open Settings > Apps > Installed apps, find Microsoft 365 or the relevant Office entry, select its menu, and choose Modify. In Windows 10, use Settings > Apps > Apps & features, select the Office entry, and choose Modify. Follow the repair choices shown. Quick Repair is the shorter initial option; if it does not help, use Online Repair if available. Online Repair needs an internet connection and can take longer. You may need to sign in or reactivate Office afterward.

Repairing Office is appropriate when the blocked path points to an Office file, or when the problem began after an Office update or installation issue. It is less likely to fix a DLL belonging to another vendor, a Windows boot file, or a policy block controlled by an organization. Keep a copy of important workbooks as a sensible precaution, even though Office repair is not intended to erase them.

Check whether an Excel add-in is involved

If Excel opens but fails when a feature or workbook loads, an add-in may be involved. To test Excel without its usual add-ins, press Windows key + R, enter excel /safe, and press Enter. This starts Excel in Safe Mode when the installation can load. On a Mac, the Windows Run command and this launch option do not apply; this specific 0xc0000428 status is a Windows error.

If Safe Mode works, disable add-ins through Excel: select File > Options > Add-ins. At the bottom, choose COM Add-ins in the Manage box and select Go; clear selected items and restart Excel normally. Excel add-ins can also be managed from the same page by choosing Excel Add-ins in the Manage box. Re-enable items one at a time to identify a likely cause, and get an updated version from the add-in publisher before using it again.

Safe Mode is a diagnostic test, not a repair for a blocked EXCEL.EXE or a Windows policy restriction. If Excel cannot start even in Safe Mode, return to the file path in the error and continue with Office repair or the appropriate administrator support.

When Windows repair or IT support is the right next step

If the message identifies a Windows file, appears during startup, or persists after Office repair, investigate Windows rather than repeatedly reinstalling Excel. On a personal PC, Windows system-file tools can check and repair protected system components. Open Terminal or Command Prompt as an administrator and run DISM /Online /Cleanup-Image /RestoreHealth, then run sfc /scannow. Let each operation finish and restart Windows if requested. These commands address Windows components; they are not a guaranteed repair for third-party add-ins or every Office file.

For additional evidence, Event Viewer may record code-integrity events. Search Windows for Event Viewer, then browse to Applications and Services Logs > Microsoft > Windows > CodeIntegrity > Operational. The relevant event may help identify the file or policy involved, but interpreting it can require administrator knowledge. On a company-managed computer, give the administrator the event details rather than changing security settings yourself.

If the problem began immediately after installing a particular third-party program or add-in, update or uninstall that program using its supported process, then restart and test Excel. Do not delete a DLL simply because it appears in the message: another application may depend on it, and removing it does not repair its signature or integrity.

What not to do

Avoid instructions that tell you to disable driver-signature enforcement, turn on test-signing mode, weaken Windows security policy, or approve an unknown file. Those changes can let untrusted code run and may only hide the symptom. They are not routine Excel troubleshooting steps. If an organization deliberately blocks a component, its IT team should decide whether the file is legitimate and whether an exception is appropriate.

Do not download a replacement DLL from a generic DLL site. The file may be the wrong version, unsafe, or unrelated to the actual cause. Obtain Office files through Office repair or an official Microsoft installation channel, and obtain third-party components from their publisher. If you suspect malware, run a scan with Windows Security or your organization’s approved security product and follow its guidance.

Alternatives if you need the workbook urgently

If Excel for Windows will not launch, Excel for the web may be a temporary option at Microsoft 365, provided your account and organization permit it. Uploading a workbook sends it to an online service, so consider confidentiality, organizational rules, macros, and feature compatibility before doing so. Some desktop-only features and VBA macros do not behave the same way in the web app.

On a separate trusted computer with Excel installed, you may be able to open a copy of the workbook while the original PC is repaired. Keep the original unchanged and avoid enabling macros in a file whose source you do not trust. The web app or another computer can help with access, but neither explains nor fixes the Windows signature failure on the affected PC.

Frequently Asked Questions

Is 0xc0000428 an Excel error or a Windows error?
It is a Windows status code that can appear while Windows is loading Excel or a file Excel uses. Excel may be the application affected, but the code does not identify a spreadsheet formula problem.

Does this error mean Excel has a virus?
No. It indicates that Windows could not validate a file under its integrity checks; corruption, an add-in, an update issue, or a security policy can also be responsible. Check the named file and use a trusted security scan if infection is a concern.

Can I fix it by reinstalling Excel?
Office repair is a reasonable step when the named file belongs to Office, but a reinstall may not help if Windows blocked a third-party DLL or a managed security policy. Identify the file and try Quick Repair before considering more extensive Office changes.

Why does Excel open in Safe Mode but not normally?
That points toward something Excel loads during a normal start, often an add-in or customization. Disable add-ins, restart normally, and re-enable them individually to narrow down the cause.

What if the code appears before Windows starts?
That is more likely a Windows startup or boot-file issue than an Excel problem. Use Windows recovery guidance or contact a qualified technician or your organization’s IT team; Office repair will not repair a blocked boot component.

Try it: the Formula Explainer: paste any formula and see each function and reference in plain English.

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Sources: Function behaviour and menu paths: Microsoft Support documentation for Excel. Method & sources

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