Windows Error Code A-Z Index: Look Up Any Code

How to Look Up Your Code in 30 Seconds

Start in the search box at the top of this page. Paste the code if you can copy it, or type it exactly as it appeared, including the 0x at the start and any leading zeros after it.

If you would rather browse, use the A-Z links for named codes and the number jump links for numbered codes. A missing zero can point to a different code, so check each character before you select an entry.

Each entry gives you one line in plain English and a link to that code's own page, where the steps are. If the same digits appear in two families, pick the entry that matches where you saw the code, such as during an update or at sign-in. Both entries lead to the same single page.

General Windows and HRESULT Codes: 0x800…

This is the largest family in the index, covering general Windows errors and HRESULT codes. HRESULT is the format many Windows programs use to pass back a result or an error. The family is drawn from the Microsoft Learn System Error Codes list and the Microsoft Learn HRESULT lists, and the entries below are in number order so you can scan down to the code you saw.

Many codes in this family start with 0x8007. In plain English, those are older Windows system errors wrapped in the 0x800 format, which is why the last part of the code matches a system error number. For example, a system error shown on its own can also appear with 0x800 added at the front. The short meaning in this index is taken from that matching system error.

The most searched entries are: 0x80004005, unspecified error, with no specific cause named. 0x80070002, Windows cannot find the file it was told to open. 0x80070005, access denied, because permission was refused. 0x80070057, incorrect parameter, so a value Windows was given is not valid. 0x80070643, an installation did not complete successfully. Each code in the list links to a different page, so pick the exact code you saw.

Select any code above to open its own page, where the steps for that code are given. Take extra care with 0x80004005. Microsoft lists it in deliberately vague terms, so its entry routes you by where the code appeared. That context helps you reach the right page on the first try. The family list continues in number order below these searched entries, using the one-line format for each code.

Windows Update Codes

Windows Update has its own set of 0x codes, and they show up in Settings under Windows Update, often next to a 'Retry' button. Each line below gives the plain meaning only, then takes you to that code's own page for the fix. That keeps update failures separate from the general 0x800 codes in the previous section.

0x80073712: some files the update needs are missing or damaged. 0x800f081f: Windows cannot find the source files it needs to finish installing the update. 0x80070422: a service Windows Update needs is turned off, so the update cannot run.

If your screen also shows a KB number, do not search by that number. A KB number names the update package itself. It is not an error code. Type the 0x code instead, with all its digits, and you will land on the right entry.

This is a short entry point, not the full list. For every other update code, go to the Windows Update Error Codes List, which covers the whole update family in one place. If your code starts with 0x800 but did not appear during an update, try the general list in the section above instead.

Stop Codes, Boot and Sign-In Codes: 0x000… and 0xC000…

Crash screens and start-up screens look different from the code families above. A stop code is shown as a name in capital letters, with a short number in parentheses after it, such as (0xEF). Write the name and number down, or take a photo of the screen before you restart, because this screen usually goes away and you rarely get a chance to copy the code later.

CRITICAL_PROCESS_DIED (0xEF): a process Windows needs to stay running has stopped; IRQL_NOT_LESS_OR_EQUAL (0x0A): something tried to use memory in a way Windows does not allow; INACCESSIBLE_BOOT_DEVICE (0x7B): Windows cannot reach the drive it starts from. Select the exact name on your screen to open its own page.

Boot and sign-in failures use a longer format that starts with 0xC000, often on a black or blue screen before Windows loads or before you can sign in. Keep the codes below separate from the stop codes above, even if the problem also stopped Windows from starting. Match the full code exactly, including the c after 0x, because one different letter or digit points to a different page.

0xc000021a: a key system process stopped during start-up, so Windows cannot continue; 0xc000000e: a device Windows needs to start cannot be found or reached. Each link goes to its page in the Won't Start and BitLocker section, where the steps for that specific code are kept.

Device Manager, Store and App Codes

Device Manager codes look different from most codes on this page. They are plain numbers with no 0x in front, written as Code 10, Code 28, or Code 43. Adding 0x to one of these numbers can send your search to the wrong family, so search in the exact form you saw.

Code 10: this device cannot start. Code 28: the drivers for this device are not installed. Code 43: Windows has stopped this device because it reported a problem. Select the code that matches your Device Manager message to open its own page.

App codes use the 0x format, even when the app name comes first. Microsoft Store 0x803F8001: the Store cannot confirm this app is licensed to your account. Camera 0xA00F4244: Windows cannot find a camera it can use. Outlook 0x800CCC0E: Outlook cannot connect to your mail server. Select your code to open its own page.

OneDrive sync codes are not listed here. They sit with the OneDrive icons, because the icon you see helps explain what the code means. Use the OneDrive icon-and-codes page to match both together.

Can't Find Your Code, or the Warning May Not Be Real

Can't find your code, or the warning may not be real

If your search found nothing, check the code again. The letter O is often typed in place of zero, and a missing leading zero changes the code. If no code is shown, search by the exact wording of the message instead.

If the code came from a pop-up urging you to call a number, pay with gift cards, or allow remote access, stop and use the Real or Fake Checker. If Windows Security or Microsoft Defender shows 'Threat Found,' go to the Defender pages.

Our sources are Microsoft Learn and Microsoft's official code lists. This is an unofficial guide, not affiliated with Microsoft. We add new codes on reader and search evidence and refresh the index after Patch Tuesday. To report a missing code, email [email protected] and say where you saw it.