Windows Error: "Not used. To be removed."

Description

The error message "Not used. To be removed." is a placeholder string used by developers inside the Windows operating system. It typically appears when a background system process, scheduled task, or registry entry attempts to call a function, service, or driver that Microsoft has deprecated (retired) but not completely erased from the system code.

Instead of crashing, the system displays this literal developer note. It most commonly occurs in the following scenarios:

• Windows Task Scheduler: An old telemetry or system maintenance task triggers a script that no longer exists.
• Corrupted System Files: A recent Windows Update left behind orphan registry keys or broken component links.
• Device Driver Conflicts: Older hardware drivers try to communicate with an obsolete Windows subsystem.

Step-by-Step Fixes

Follow these steps in order to resolve the error.

Step 1: Run SFC and DISM Tools

Windows has built-in repair tools that scan for broken system components and replace them with fresh copies.

1. Press the Windows Key, type cmd, right-click Command Prompt, and select Run as administrator.
2. Type the following command and press Enter: DISM.exe /Online /Cleanup-image /Restorehealth
3. Wait for the process to reach 100% (this may take several minutes).
4. Type the following command and press Enter: sfc /scannow
5. Restart your computer after the scan finishes.

Step 2: Disable Broken Tasks in Task Scheduler

If the error pops up at specific times or during startup, a ghost scheduled task is likely the trigger.

1. Press Windows Key + R to open the Run dialog box.
2. Type taskschd.msc and press Enter to open Task Scheduler.
3. Click on Task Scheduler Library in the left sidebar.
4. Look through the list of tasks in the center pane. Look specifically for tasks with unusual names, tasks related to old software you uninstalled, or tasks pointing to missing .exe files.
5. Right-click the suspicious task and select Disable.
6. Expand the Microsoft -> Windows folders in the left sidebar to check for native tasks that might be corrupted, focusing on folders like Application Experience or Customer Experience Improvement Program.

Step 3: Clean Boot the System

This step helps identify if a third-party startup program or non-Microsoft service is causing the error.

1. Press Windows Key + R, type msconfig, and press Enter.
2. Go to the Services tab at the top.
3. Check the box next to Hide all Microsoft services at the bottom.
4. Click the Disable all button.
5. Go to the Startup tab and click Open Task Manager.
6. Disable every startup item by right-clicking each one and selecting Disable.
7. Close Task Manager, click Apply and OK in the System Configuration window, and restart your PC.
8. If the error disappears, re-enable your services one by one to find the software causing the conflict.

Step 4: Clear the Windows Update Cache

Since this error often stems from incomplete updates or abandoned update packages, clearing the cache forces Windows to rebuild its database.

1. Open Command Prompt as administrator (as shown in Step 1).
2. Stop the update services by typing these commands one by one, pressing Enter after each: net stop wuauserv net stop bits
3. Press Windows Key + R, type C:\Windows\SoftwareDistribution\Download and press Enter.
4. Delete all files and folders inside this folder (Press Ctrl + A, then Delete).
5. Return to the Command Prompt window and restart the services by running: net start wuauserv net start bits
6. Restart your computer.