Windows System Errors

System26 error codes

Reference list of 26 Windows system errors with meanings, common causes, and related context.

About Windows System Errors

Windows system errors use a dual-layer reporting model: numeric system error codes (0–15999) for common operating-system failures and structured HRESULT values (32-bit hexadecimal codes like 0x80070005) for COM, Windows API, and application errors. HRESULT values encode severity (bit 31), facility (bits 16–26), and code (bits 0–15) in a single 32-bit value.

Many Windows error codes encountered in practice are HRESULT values from the 0x8007xxxx range, where the 0x7 facility indicates a Win32 system error mapped into HRESULT format. For example, 0x80070005 maps to Win32 error 5 (ERROR_ACCESS_DENIED), and 0x80070002 maps to Win32 error 2 (ERROR_FILE_NOT_FOUND). Understanding this mapping helps narrow down the root cause from the hexadecimal code.

This collection documents 26 Windows system error codes, covering common HRESULT values from Windows Update (0x8024xxxx), access-denied errors (0x80070005), file-not-found errors (0x80070002), and system component failures. Each entry explains the HRESULT structure, the underlying Win32 error it maps to, and common scenarios where it appears.

Severity

Showing 26 of 26 error codes

0x80070005
High

Access Denied

3 common causes
0x80070643
High

Fatal error during installation

3 common causes
0x80244017
High

WU_E_PT_HTTP_STATUS_DENIED

3 common causes
0x80040154
High

Class not registered

3 common causes
0x80073712
High

Component Store Corrupted — a required Windows Update component is damaged

3 common causes
0x800F0922
High

Update Installation Failed — update service connection or reserved partition issue

3 common causes
0x8007045d
High

I/O Device Error — Windows cannot perform an input/output operation on the specified device

3 common causes
0x80070424
High

Required Service Missing — Windows cannot find a service needed for the operation

3 common causes
0x80072EE2
High

Operation Timed Out — Windows Update waited too long for a response

3 common causes
0x80073701
High

Assembly Missing — servicing stack could not find a required component package

3 common causes
0x80070490
High

Element Not Found — Windows could not locate a required servicing component

3 common causes
0xC1900101
High

Driver Compatibility Failure — Windows upgrade rolled back after a driver-related crash

3 common causes
0x80070002
Medium

File Not Found

3 common causes
0x80240034
Medium

Update Failed

3 common causes
0x800F081F
Medium

Source Files Not Found

3 common causes
0x80004005
Medium

Unspecified Error

3 common causes
0x80070020
Medium

The process cannot access the file because it is being used by another process

3 common causes
0x80070422
Medium

The service cannot be started, either because it is disabled or has no enabled devices

3 common causes
0x80070057
Medium

0x80070057 (E_INVALIDARG) — one or more arguments supplied are invalid

4 common causes
0xc000021a
Medium

Fatal System Error — a critical Windows subsystem process terminated, causing the system to halt

3 common causes
0x80070070
Medium

Not Enough Disk Space — the target volume has insufficient free space for the operation

3 common causes
0x8007000D
Medium

Invalid Data — Windows received update data it could not parse

3 common causes
0x80244022
Medium

Service Unavailable — the update endpoint returned a temporary server-side failure

3 common causes
0x8024402C
Medium

Name Resolution Failure — Windows Update could not resolve the required server name

3 common causes
0x800705B4
Medium

Operation Timeout — a required Windows task did not finish in time

3 common causes
0x8024200D
Medium

Update Content Incomplete — the downloaded update package could not be used

3 common causes

Frequently Asked Questions

0x80070005 corresponds to ERROR_ACCESS_DENIED — the operation was blocked due to insufficient permissions. The 0x8 prefix indicates failure severity, the 0x7 facility indicates a Win32 source, and 0x0005 maps to Win32 error code 5 (Access Denied).

An HRESULT is a 32-bit value where bit 31 indicates severity (1 = failure), bits 16–26 indicate the facility (0x7 = Win32, 0x4 = RPC, 0xA = Windows Update), and bits 0–15 indicate the specific error code. For 0x8007xxxx codes, the last four hex digits map directly to the Win32 error number.

Windows Update errors in the 0x8024xxxx range indicate problems with the update delivery mechanism: 0x80244017 means a WU_E_PT_HTTP_STATUS_DENIED (proxy or authentication issue), and 0x80244022 means a WU_E_PT_HTTP_STATUS_SERVICE_UNAVAIL (the update server is temporarily unavailable).