Edge Crashes on Launch After Windows 10 KB5006670

You install Windows 10 update KB5006670, reboot, and then click the Edge icon. The browser flashes for a second, then vanishes. No error message, no crash dialog—just nothing. You try again, same result. This is a known side effect of that specific update, and it usually hits people who had Edge open during the update or who have a slightly corrupted Edge profile.

The root cause is that the update messes with Edge's local state files. Specifically, the update replaces some system files that Edge depends on, but the old profile data (cookies, history, extensions) doesn't match the new file versions. Edge tries to load that mismatched profile and dies on startup. It's not your fault, and reinstalling Windows won't help. The fix is to reset Edge's profile or do a clean reinstall.

I'll walk you through both. Start with the reset because it keeps your bookmarks (mostly). If that fails, we'll do a full reinstall.

Method 1: Reset Edge Settings (Keeps Bookmarks)

1. Close Edge completely. Check the system tray (bottom-right corner) for any Edge icon—right-click it and choose 'Exit'. If you can't find it, open Task Manager (Ctrl+Shift+Esc), look for any 'Microsoft Edge' processes, select each one, and click 'End Task'.
2. Open File Explorer by pressing Win + E.
3. In the address bar, paste this path and press Enter:

   %LOCALAPPDATA%\Microsoft\Edge\User Data

   You'll see a folder called Default and possibly some other files like Local State.
4. Right-click the Default folder, choose Rename, and type Default.old. Press Enter. Also rename Local State to Local State.old if you see it.
5. Now launch Edge. It will create a fresh Default folder and start clean. You'll see the first-run page. Your bookmarks are gone, but you can get them back from the Default.old folder if you need them—just copy the Bookmarks file from Default.old to the new Default folder later.
6. Check if Edge opens normally. It should. If it does, you're done. If not, move to Method 2.

Method 2: Reinstall Edge Completely

If the reset didn't work, the browser files themselves are broken. Here's how to rip it out and start over.

1. Press Win + I to open Settings. Go to Apps → Apps & features.
2. In the search box, type Edge. You'll see 'Microsoft Edge' in the list. Click it, then click Uninstall. Confirm if prompted.
3. After it uninstalls, reboot your PC. Yes, reboot—don't skip this.
4. When you're back, open the new Edge that Windows automatically reinstalls (it's built into Windows 10, so it comes back after reboot). It'll be a basic version.
5. Go to edge://settings/help in the address bar. Edge will check for updates and install the latest version. Wait for it to finish.
6. Close and reopen Edge. It should work now.

Why This Happens

Think of it like this: KB5006670 updates a bunch of system DLLs. Edge uses those DLLs. But your Edge profile was created with older versions. When Edge starts, it tries to read its profile files, and the file headers don't match what the new DLLs expect. Result: a crash. The reset forces Edge to create a new profile that matches the updated files.

The reinstall method is more thorough—it replaces the browser executable and all its components. But it nukes your extensions and saved passwords, so back those up if you can. Actually, you can't back up passwords easily, so just remember to export them from the old profile if you can still get it open. If Edge won't open at all, you might be out of luck there.

What If It Still Fails?

If neither method works, you're looking at a deeper problem. Here's what to do:

• Check for other pending Windows updates. Sometimes KB5006670 has a follow-up patch that fixes the Edge issue. Go to Settings → Update & Security → Windows Update, and click Check for updates. Install everything and reboot.
• Run the System File Checker. Open Command Prompt as administrator (right-click Start, choose 'Command Prompt (Admin)'), then type:

  sfc /scannow

  Let it finish. It'll replace corrupted system files that might be causing Edge to crash.
• If you use any third-party antivirus (besides Windows Defender), temporarily disable it and test Edge. Some AVs conflict with Edge after updates.
• As a last resort, create a new Windows user account and try Edge there. If it works, your old profile is beyond repair—you can copy your files over manually.

This fix has worked for every tech I've talked to. Start with the reset—it's quick and painless. If that fails, the reinstall is your guarantee. Don't panic about losing bookmarks; you can export them from the Default.old folder.