Windows & BSOD · high

How to fix0x800F081F

Windows Update Repair Failure (0x800F081F)

What this error means

Required source files were unavailable (0x800F081F). The next step depends on whether the message came from Windows Update, DISM, or .NET feature installation.

Applies to
Windows 11; Windows 10 interfaces may differ
Difficulty
Beginner to intermediate
Before changes
Some checks require restart or system changes

Documentation checked: 2026-09-28 · Editorial guide checked against the linked documentation; not tested on every hardware configuration.

Before you begin

Back up important files. Save your work and record the exact message before changing anything. If Windows cannot start, see the startup guide.

Work through these checks

0 of 4 complete
01Identify which operation needs source files
  1. Record whether you were enabling .NET Framework 3.5, installing an update, or running DISM.
  2. Record Windows version and build with winver.
What to expect

You know which servicing operation failed.

If it does not help

Do not use a repair command copied for a different operation.

Browse related errors
02For .NET installation, check the source and policy
  1. On a managed PC, ask IT whether optional component installation can obtain files from Windows Update.
  2. If an alternative source is required, follow Microsoft’s .NET installation guidance for compatible Windows media.
What to expect

The installation has an allowed, compatible source.

If it does not help

Do not change organisation policy yourself or download individual system files from an unrelated site.

Browse related errors
03For component repair, follow the repair sequence
  1. If component repair is appropriate, open Command Prompt as administrator. Run DISM.exe /Online /Cleanup-image /Restorehealth.
  2. Only after DISM reports success, run sfc /scannow and allow verification to finish.

These tools can change system files. Back up important data and keep the device powered.

What to expect

The tools report whether the image and protected files were repaired.

If it does not help

If DISM still reports missing source files, record its log path and obtain a matching source through official guidance; do not repeat unchanged commands.

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04Prepare a focused support request
  1. Collect the KB number, Windows build, failure time, and checks already tried.
  2. Use the support link for that specific update or contact your organisation’s IT team if the computer is managed. Share logs privately only after checking them for personal data.
What to expect

Support can distinguish this incident from unrelated failures with the same numeric code.

If it does not help

Keep the backup and the original error details; avoid undocumented registry or partition changes.

Browse related errors

Possible causes

  • Corrupt component store database files preventing system repair.
  • Missing local source installation files when executing the DISM command with the /Source parameter.
  • Incompatible or incomplete Windows updates installed in the servicing stack.

Sources & further reading