Windows System Error Codes List: What They Mean & How to Fix Them

Encountering a cryptic hexadecimal string on your screen can bring your workflow to an instant halt. This Windows system error codes list cuts through the jargon, giving you plain-language explanations and actionable fixes for the errors Windows users hit most often — whether you’re on Windows 10 or Windows 11. Bookmark it, search it, and get back to work faster.

What Are Windows Error Codes?

Windows error codes are numeric identifiers — usually displayed in hexadecimal (e.g. 0x80070005) — that Windows generates when something goes wrong. Each code maps to a specific problem defined in Microsoft’s WinError.h header file, which forms the backbone of the official Windows Win32 System Error Codes documentation on Microsoft Learn. There are thousands of defined codes, but the same handful account for the vast majority of real-world issues. The guide below focuses on those.

How to Read a Windows Error Code

Windows error codes follow a predictable structure. The leading 0x prefix signals a hexadecimal value. The digits that follow encode the severity, facility (the subsystem that threw the error), and the specific error number. You don’t need to memorise the bit structure — what matters is knowing the common Windows error codes and their remedies, which is exactly what this reference provides.

• 0x8xxxxxxx codes — typically Windows Update, COM, or system permission errors.
• 0xCxxxxxxx codes — often critical application or boot failures.
• 0x000000xx codes — classic Blue Screen of Death (BSOD) stop codes.
• Decimal codes (e.g. Error 5, Error 2) — legacy Win32 errors, still widely seen in Event Viewer.

Common Windows Error Codes: Access & Permission Errors

0x80070005 — Access Denied

What it means: The operation was blocked because the current user or process lacks the required permissions. This is one of the most frequent entries on any Windows error code list, appearing during Windows Update, software installation, or when writing to a protected directory.

Quick fix:

1. Right-click the installer or the app and choose Run as administrator.
2. Open Settings → Windows Update → Advanced Options and pause/resume updates, then retry.
3. Run the Windows Update Troubleshooter (Settings → System → Troubleshoot → Other troubleshooters).
4. If the error appears in a corporate environment, contact your IT admin — Group Policy may be restricting access.

0x80004005 — Unspecified Error

What it means: A catch-all code that translates to “unspecified error.” It commonly surfaces when accessing shared network folders, extracting ZIP archives, or running virtual machines. The vague name hides a range of root causes, mostly permission or file-lock issues.

Quick fix:

• For ZIP files: right-click → Properties → Unblock, then try again.
• For network shares: ensure SMB 1.0 is enabled if connecting to older NAS devices.
• For VMs (VirtualBox/Hyper-V): run sfc /scannow from an elevated Command Prompt and reboot.

Common Windows Errors During Updates

0x80070002 — File Not Found

What it means: Windows Update (or another component) cannot find a required file. This common Windows error often appears when update cache files become corrupted or a previous update left the system in an inconsistent state.

Quick fix:

1. Stop the Windows Update service: open Command Prompt as admin and run net stop wuauserv.
2. Delete the contents of C:\Windows\SoftwareDistribution\Download.
3. Restart the service: net start wuauserv, then retry the update.

0x8007000D — Invalid Data

What it means: Windows Update encountered data it cannot process — usually corrupted system files or a damaged update package. Running the built-in System File Checker and DISM commands resolves this in most cases.

Quick fix: Run these two commands in sequence from an elevated Command Prompt:

1. DISM /Online /Cleanup-Image /RestoreHealth
2. sfc /scannow

Reboot and retry Windows Update. For a real-world example of a stubborn Windows Update failure, see our detailed walkthrough on the Fix Windows 11 Update 0x800f0922 Error — the same DISM approach applies to 0x8007000D.

0x800f0922 — EFI System Partition Too Small

What it means: This error blocks feature updates when the EFI System Partition has less than 500 MB of free space, or when a VPN driver interferes with the update stack. It is a known blocker for several Windows 11 cumulative updates and frequently stops the download at around 35%.

Quick fix: Disconnect any VPN, disable third-party antivirus temporarily, and retry. If the EFI partition is genuinely too small, use a third-party partition tool to resize it — or perform an in-place repair upgrade using the Windows 11 ISO.

Windows Error Code List: Application & Runtime Errors

0xc0000135 — Application Unable to Start

What it means: An application has failed to start because a required .NET Framework version is missing or corrupted. This is a top-ranked entry on any common Windows errors list and affects both Windows 10 and Windows 11. The error sometimes spikes after a major Windows update removes an older .NET component.

Quick fix:

• Go to Control Panel → Programs → Turn Windows features on or off.
• Enable .NET Framework 3.5 (includes 2.0 and 3.0) and click OK.
• If that fails, download and manually install the required .NET version from the Microsoft website.
• Run sfc /scannow to repair any corrupted system files contributing to the error.

0xc000007b — Invalid Image Format

What it means: Windows tried to run a 64-bit application using 32-bit system libraries (or vice versa). It most often occurs after a software conflict, a failed installation, or a corrupted Visual C++ redistributable package.

Quick fix:

1. Uninstall and reinstall all Microsoft Visual C++ Redistributable packages from the official Microsoft Download Center.
2. Reinstall the affected application.
3. If the issue persists, run DISM /Online /Cleanup-Image /RestoreHealth.

0xc000021a — Fatal System Error (BSOD)

What it means: Windows encountered a fatal error in the Winlogon or CSRSS subsystem and could not recover. This blue screen error typically follows a failed Windows Update, a driver conflict, or a corrupted system file. It prevents Windows from booting normally.

Quick fix:

• Boot into Windows Recovery Environment (RE) by holding Shift while clicking Restart.
• Choose Troubleshoot → Advanced Options → Startup Repair.
• If Startup Repair fails, use System Restore to roll back to a point before the error appeared.
• As a last resort, perform a clean installation of Windows using a fresh licence key.

Device Manager Error Codes

Device Manager uses decimal error codes (called “Code” numbers) rather than hexadecimal. These appear under the Device status field in a hardware device’s Properties window and are part of every complete Windows error code list.

Code 10 — Device Cannot Start

The most common Device Manager error. It means the hardware device failed to start. Update or roll back the device driver: right-click the device → Update driver. If that fails, uninstall the device and reboot to let Windows re-detect it.

Code 28 — Drivers Not Installed

Windows found the hardware but has no driver for it. Download the correct driver from the manufacturer’s website and install manually, or use Windows Update to search for it automatically.

Code 43 — Device Stopped (User Request or Failure)

The device has reported a problem and Windows stopped it. This is common with USB devices and GPUs. Uninstall the driver completely (including via Display Driver Uninstaller for GPUs), then reinstall the latest version from the manufacturer.

How to Look Up Any Windows Error Code Yourself

For any code not in this Windows system error codes list, Microsoft provides two official resources:

• Microsoft Error Lookup Tool (Err.exe) — a free command-line utility that decodes any error code instantly.
• Microsoft Learn (learn.microsoft.com) — search the full WinError.h reference for every defined code and its description.
• Windows Event Viewer — open it via eventvwr.msc and check Windows Logs → System or Application for detailed context around any error code.

Event Viewer is particularly valuable because it pairs the error code with the exact process, timestamp, and surrounding events — turning a cryptic hex string into an actionable diagnosis in seconds.

Prevent Errors Before They Start: Keep Windows Fully Licensed

A surprising number of Windows error codes — particularly update-related ones like 0x80070005 and 0x800f0922 — are far more likely to appear on machines running with a generic or pirated activation key. A genuine, fully activated Windows licence ensures your system receives every security patch and feature update without restrictions, which directly reduces the frequency of errors in this list.

ShopKeyOnline offers genuine Windows 11 licences at competitive prices. The Microsoft Windows 11 Pro Retail key is available from just €17.95 and is delivered by email within minutes. If you need a combined productivity solution, the Windows 11 Pro + Office 2021 Pro Plus bundle is available from €36.90 — ideal for home or professional use. A clean, activated install is the single best starting point for a trouble-free Windows experience.

Quick Reference: Windows Error Code Cheat Sheet

FAQ: Windows Error Codes

What does the 0x prefix mean in a Windows error code?

The 0x prefix indicates the number is written in hexadecimal (base-16) notation. Windows uses hex because each code packs severity, subsystem (facility), and error-number bits into a single compact value. You can convert any hex code to decimal using the Windows Calculator in Programmer mode.

Can I look up a Windows error code list in Event Viewer?

Yes. Open Event Viewer by pressing Win + R and typing eventvwr.msc. Navigate to Windows Logs → System or Application. Each event entry shows the error code alongside the source process and a human-readable description — far more context than a raw hex value alone provides.

Why does 0x80070005 keep coming back after I fix it?

Recurring 0x80070005 errors usually point to a persistent permission problem — either a Group Policy setting, a locked system folder, or a third-party security product overriding Windows Update permissions. Run the Windows Update Troubleshooter, check that the Windows Update service account has the correct folder permissions under C:\Windows\SoftwareDistribution, and temporarily disable third-party antivirus to isolate the cause.

Is 0xc0000135 dangerous?

No — it is not a sign of deep system corruption. It simply means the application you launched requires a version of the .NET Framework that is not currently installed or enabled. Enabling .NET Framework 3.5 through Windows Features or downloading the correct runtime from Microsoft resolves it without any risk to your data.

What is the fastest way to fix most common Windows errors?

For the majority of entries in this Windows error code list, two commands fix the underlying issue: DISM /Online /Cleanup-Image /RestoreHealth followed by sfc /scannow, both run from an elevated Command Prompt. These commands repair the Windows component store and replace corrupted system files, resolving a wide range of update, application, and runtime errors in one pass.