Fix ERROR_NO_MATCH (0X00000491) in Windows Search

What's happening with ERROR_NO_MATCH (0X00000491)?

You're trying to search for a file, an email, or a setting in Windows, and instead of results you get error 0X00000491. The message says "There was no match for the specified key in the index." This pops up most often after a Windows update (like the October 2023 cumulative update for Windows 11 22H2), or if you've recently moved or deleted a ton of files. The search index gets confused — it holds a reference to a key that's gone or broken.

The fix is straightforward. We'll start with the simplest option (takes 30 seconds) and move to more involved fixes. Stop when the error disappears.

Fix 1: Rebuild the Windows Search Index (30 seconds)

This is the first thing to try. It forces Windows to rebuild the entire index from scratch. Your files aren't touched — just the database that speeds up searching.

1. Open the Control Panel. Press Windows Key + R, type control, and hit Enter.
2. Click on Indexing Options. If you don't see it, set the view to "Large icons" or "Small icons" in the top-right corner.
3. In the Indexing Options window, click the Advanced button. You'll need admin permission — click Yes if prompted.
4. Under the "Troubleshooting" section, click the Rebuild button.
5. A warning pops up: "Rebuilding the index might take a long time." Click OK.
6. Close the Indexing Options window.

After clicking Rebuild, you should see the index status change to "Indexing complete" eventually — but it might say "Indexing speed reduced due to user activity" for a while. That's fine. Let it finish. The error should be gone once the rebuild is done. If not, move to the next fix.

Fix 2: Reset the Search Index via Services (5 minutes)

If rebuilding didn't work, the Windows Search service itself might be stuck. We'll stop it, delete the index database files, and restart it clean.

1. Press Windows Key + R, type services.msc, and hit Enter.
2. Scroll down to Windows Search. Right-click it and select Stop. Wait a few seconds until the Status column shows blank.
3. Open File Explorer. In the address bar, paste this path and press Enter:
   C:\ProgramData\Microsoft\Search\Data\Applications\Windows\
4. You'll see a file named Windows.edb (the index database). Right-click it and choose Delete. If Windows says the file is in use, go back to Services and double-check that Windows Search is stopped. If it's still running, restart the computer in Safe Mode and try again.
5. Go back to the Services window. Right-click Windows Search again and select Start.
6. Close Services.

After starting the service, Windows will create a fresh Windows.edb file. The index rebuilds automatically — this can take 15-30 minutes depending on how many files you have. During that time, the error 0X00000491 should not appear. If it does, or if you can't delete the edb file, move to the advanced fix.

Fix 3: Fix the Registry Key (15+ minutes — only do this if the other fixes failed)

This error can also come from a corrupt registry key under the Windows Search path. I've seen this after failed Windows updates or registry cleaner tools that over-aggressively prune keys. Editing the registry is risky — one wrong change can break Windows. Back up the registry first.

Back up your registry: Open Registry Editor (Windows Key + R, type regedit, hit Enter). Click File > Export. Save the backup somewhere safe, like your Desktop. Name it something like "RegistryBackupBeforeFix.reg".

Now, to fix the specific key for ERROR_NO_MATCH:

1. In Registry Editor, go to this path:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Search\IndexSetup
2. On the right, look for a value named IndexerStatus. If it exists, right-click it and select Modify. Change the Value data to 0 (zero). Click OK.
3. Now navigate to this second path:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Search\Gather\Windows\SystemIndex
4. On the right, find the value named Status. If it's there, set it to 0 as well. If it's missing, right-click an empty space, select New > DWORD (32-bit) Value, name it Status, and set it to 0.
5. Close Registry Editor.
6. Restart your computer. Not just a logoff — a full restart.

After restart, Windows Search should start fresh. If the error still shows up, there's a deeper corruption. Run the System File Checker tool: open Command Prompt as admin (right-click Start > Command Prompt (Admin) or Terminal (Admin)), then type sfc /scannow and let it finish. Then run DISM /Online /Cleanup-Image /RestoreHealth. Those fix system files that might be breaking the search engine.

That's it. Start with Fix 1 — most people won't need to go further. If you do end up in the registry, take your time and double-check each step. You've got this.