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The InstanceSetup callback (PFLT_INSTANCE_SETUP_CALLBACK) is called twice for the same volume

yuval0x92yuval0x92 Member Posts: 5


While developing my minifilter, I noticed that the InstanceSetup callback (PFLT_INSTANCE_SETUP_CALLBACK) is called twice for every NTFS volume.
This results in 2 instances of my filter on the same volume (at different altitudes).

So my question is as follows:
1. Why does it happen?
2. How can I prevent it?



  • Dejan_MaksimovicDejan_Maksimovic Member - All Emails Posts: 374
    via Email
    That should not be the case. Recheck your setup.
  • rod_widdowsonrod_widdowson Member - All Emails Posts: 1,173

    This results in 2 instances of my filter on the same volume (at different altitudes).

    Check you registry settings. It is quite feasible to have the same filter at multiple altitudes, but you have to tell it to do so.

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