Clean up com ports in use

How to clean up com ports in use by the system which are actually not in use.



  1. Run REGEDIT to edit the Windows Registry.
  2. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\COM Name Arbiter
  3. Now on the right panel, you can see the key ComDB. Right-click it and click modify
  4. In value Data section select all and delete reset to Zero (0)
  5. Its 32 bytes with 8 bits in each byte. A set bit makes a port number (1...256) reserved. enter image description here
  6. Close Registry editor and then restart your computer. All COM ports are now Free.
  7. You may need to reinstall any USB-to-serial converter.


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