Fix Print Spooler Crash by Removing Print Monitors

A constantly crashing Windows Print Spooler service is frequently caused by corrupted, outdated, or incompatible third-party print monitors. When the spooler starts, it loads all registered print monitors into memory; if a single monitor fails, the entire spooler service crashes. This guide details how to access the Windows Registry, identify non-default “rogue” print monitors, safely back them up, and remove them to permanently resolve spooler crashes.

Step 1: Stop the Print Spooler Service

Before modifying any registry entries, ensure the Print Spooler service is stopped.

1. Press Win + R, type services.msc, and press Enter.
2. Scroll down to locate Print Spooler.
3. Right-click Print Spooler and select Stop.

Alternatively, open Command Prompt as Administrator and run:

net stop spooler

Step 2: Navigate to Print Monitors in the Registry

1. Press Win + R, type regedit, and press Enter to open the Registry Editor.

2. Navigate to the following path in the registry tree:

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Print\Monitors

Step 3: Back Up the Monitors Key

Always create a backup before modifying the registry to allow easy restoration if needed.

1. Right-click the Monitors folder in the left pane.
2. Select Export.
3. Choose a safe location (such as your Desktop), enter a filename like Monitors_Backup.reg, and click Save.

Step 4: Identify Default vs. Rogue Monitors

Under the Monitors key, you will see several sub-keys. The standard, safe default monitors built into modern Windows operating systems are:

• AppMon
• BJ Language Monitor
• Local Port
• Microsoft Shared Fax Monitor
• Standard TCP/IP Port
• USB Monitor
• WSD Port

(Note: Older systems may also include AppleTalk Printing Devices or LPR Port).

Any key not included in the standard list above is a third-party monitor (often associated with software from HP, Lexmark, Canon, Epson, or PDF printers). These third-party entries are the potential rogue monitors causing the crash.

Step 5: Remove the Rogue Monitors

1. Identify any key under Monitors that is not a default Windows monitor.
2. Right-click the rogue key (e.g., HP Master Monitor or a custom vendor port monitor).
3. Select Delete and confirm the prompt.
4. Repeat this process for all non-default third-party monitors.

Step 6: Restart the Print Spooler Service

1. Close the Registry Editor.

2. Open Command Prompt as Administrator and run:

   net start spooler

3. Verify that the Print Spooler stays running without crashing.

Once the service is stable, test printing. If specific printers stop working because their custom port monitor was removed, reinstall the printer using standard Windows TCP/IP or USB ports rather than manufacturer-specific port software.