Where to Find Print Processors in Windows Registry

This article explains the exact Windows Registry paths where print processors, custom data types, and print spool handlers are cataloged. It outlines the specific keys within the HKEY_LOCAL_MACHINE hive that control how the Windows Print Spooler service interprets, processes, and routes print jobs across different system architectures.

Registry Location for Print Processors

The Windows Print Spooler stores registered print processors under the architecture-specific Environments subkey within the Registry.

The base path is:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Print\Environments\

Depending on your system architecture, navigate to the appropriate subfolder:

• 64-bit Windows:
  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Print\Environments\Windows x64\Print Processors\
• 32-bit Windows:
  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Print\Environments\Windows NT x86\Print Processors\
• ARM64 Windows:
  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Print\Environments\Windows ARM64\Print Processors\

Under the Print Processors key, each installed print processor appears as a distinct subkey (for example, winprint or vendor-specific processors like hpzpnp):

...\Print Processors\<PrintProcessorName>

Associated Values and Data Types

Within each individual print processor key:

• Driver: A REG_SZ string value containing the filename of the print processor DLL (e.g., winprint.dll), typically located in C:\Windows\System32\spool\prtprocs\<architecture>\.
• Data Types: While standard print data types (such as RAW, RAW [FF appended], RAW [FF auto], NT EMF, and TEXT) are exposed programmatically by the processor DLL via the EnumPrintProcessorDatatypes API function, custom configurations or specific driver mappings may define subkeys or parameters directly under the respective print processor key.

Registry Locations for Spool Handlers and Providers

The Print Spooler relies on additional components alongside print processors to handle job routing and port communication:

1. Print Providers

Print providers direct print jobs to local or network destinations. They are cataloged at:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Print\Providers\

• LanMan Print Services: Handles network print shares via SMB.
• Internet Print Provider: Handles IPP-based queues.

2. Print Monitors (Port and Language Monitors)

Port handlers and custom bidirectional communication filters are registered under:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Print\Monitors\

Each subkey under Monitors defines the specific monitor DLL responsible for communicating with the physical or virtual destination port.