Bootstrapper Missing (watchdog_bootstrapper_missing)

Symptoms

When launching ComfyLauncher, an error dialog appears saying "ModelFinder.Bootstrapper.exe not found" and ComfyUI fails to start.

Root Cause

ComfyLauncher uses ModelFinder.Bootstrapper.exe as a helper process to start and manage ComfyUI. This file is located in the installation directory (default %LocalAppData%\ModelFinder), alongside ModelFinder.exe.

In the vast majority of cases, this file goes missing because antivirus software quarantines or deletes it. Because the bootstrapper is a small, unsigned executable, heuristic detection tends to flag it as "suspicious" and automatically move it to quarantine. The three most common offenders are:

• Windows Defender (built into Windows)
• 360 Security Guard
• Huorong Security

Severity

High — without the bootstrapper, ComfyUI cannot start at all.

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Solution

Step 1: Check whether the file exists

Open the installation directory and verify that ModelFinder.Bootstrapper.exe is present. The default installation path is:

%LocalAppData%\ModelFinder

Paste the path above into the File Explorer address bar to navigate there. If the file is missing, it has been deleted or quarantined by your antivirus software. Continue with the steps below.

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Step 2: Restore the file and add it to the allowlist

Follow the instructions for your antivirus software.

Windows Defender

Check quarantine history (GUI)

1. Open "Windows Security" (search for "Windows Security" in the Start menu)
2. Click "Virus & threat protection"
3. Click "Protection history"
4. Look for entries related to ModelFinder
5. If found, click the entry and select "Actions" -> "Restore"

Check quarantine history (PowerShell)

Open PowerShell as Administrator and run the following command to view recent threat detections:

Get-MpThreatDetection | Select-Object -First 20 | Format-List DetectionID, ActionSuccess, Resources

You can also use the Defender command-line tool to list all quarantined files:

& "$env:ProgramFiles\Windows Defender\MpCmdRun.exe" -Restore -ListAll

Add an exclusion directory

GUI method:

1. Open "Windows Security" -> "Virus & threat protection"
2. Under "Virus & threat protection settings", click "Manage settings"
3. Scroll down to "Exclusions" and click "Add or remove exclusions"
4. Click "Add an exclusion" -> "Folder"
5. Select the ComfyLauncher installation directory (default %LocalAppData%\ModelFinder)

PowerShell method (requires Administrator privileges):

Add-MpPreference -ExclusionPath "$env:LOCALAPPDATA\ModelFinder"

Verify the exclusion was added successfully:

Get-MpPreference | Select-Object -ExpandProperty ExclusionPath

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360 Security Guard

Restore quarantined files

1. Open the 360 Security Guard main window
2. Click "Trojan Scan" (or "Security Protection Center")
3. Go to the "Quarantine" or "Recovery" section
4. Find the files related to ModelFinder, select them, and click "Restore"

Add a trusted directory

1. Open the 360 Security Guard main window
2. Click the security shield icon at the top to enter the "Security Operations Center"
3. Switch to the "Trusted Zone" tab
4. Click "Add Directory"
5. Select the ComfyLauncher installation directory (default %LocalAppData%\ModelFinder)
6. Click "OK" in the confirmation dialog

If you are using 360 Security Guard Speed Edition, the navigation may differ slightly, but the trusted zone feature is in a similar location.

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Huorong Security

Restore quarantined files

1. Open the Huorong Security main window
2. Click "Security Log" on the left sidebar
3. Find the blocked ModelFinder.Bootstrapper.exe entry
4. Click "Restore" to recover the file

Add a trusted directory

1. Open the Huorong Security main window
2. Click the menu button in the top-right corner (three horizontal lines icon)
3. Click "Trusted Zone" in the dropdown menu
4. Click "Add Folder"
5. Select the ComfyLauncher installation directory (default %LocalAppData%\ModelFinder)
6. Confirm the addition

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Step 3: Reinstall ComfyLauncher

If you cannot find the deleted file in the quarantine area, reinstall to restore the missing file:

1. Complete the allowlist setup above first — otherwise the file will be deleted again after reinstalling
2. Download the latest version of ComfyLauncher from the official source
3. Install to the same directory

Reinstalling will not affect your existing ComfyUI environments or downloaded models.

After installation, launch ComfyLauncher and confirm the bootstrapper-missing error no longer appears.

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Still not resolved?

If the problem persists after following the steps above, contact support via the "Contact Us" button in the app and provide the following information:

• Name and version of your antivirus software
• Full path of your installation directory
• Whether the quarantine area contains any ModelFinder-related entries