#9 Uninstall com0com leaving registry entries behind

John Ludwig

When com0com is removed/uninstalled from SOME (not all) machines, it will occationally
leave behind some of the registry keys

When things are installed properly, the following keys exist in the registry:

HKLM SYSTEM\CurrentControlSet\Enum\com0com\ port\ CNCA0\
Device Parameters

HKLM SYSTEM\CurrentControlSet\Enum\com0com\ port\ CNCB0\ Control
Device Parameters

After a successful uninstall only one high-level key remains:
HKLM SYSTEM\CurrentControlSet\Enum\com0com\

The problem is that for some reason, on a few machines, the uninstall leaves behind
a partial key:

HKLM SYSTEM\CurrentControlSet\Enum\com0com\ port\ CNCA0\
But the rest of the keys have been removed.

This left-behind key cannot be manually removed without manually changing the permissions.

Because of a company wide requirements for complete uninstalls, we can NOT leave these registry keys
behind on a PC after an uninstall has supposed to have been performed.

Do you know a cause of why these registry keys could be left behind?
Is there a fix for this condition?? Is this a known bug to uninstalling com0com?
Is there a work around for this?

Any help would be greatly appreciated


  • The com0com's uninstaller does not remove those keys itself.
    So it's possible a Windows bug.
    The possible reason is that Enum\com0com\port\CNCA0\logConf or Enum\com0com\port\CNCA0 used by other process while uninstalling.
    Check setupc's output for "Reboot required." message (need "setupc --silent uninstall" before "uninstall /S").
    Possible after reboot those keys will be removed automatically by Windows.
    A possible work around is to install ports again and then uninstall.

    • status: open --> pending
    • status: pending --> closed
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