FltMgr initialized notification


I have one filter driver which implements disk device filter and FS minifilter. When PC boots my DriverEntry is called and I can not call FltRegisterFilter since FltMgr is not initialized yet in this very soon phase of booting. I get error code STATUS_FLT_NOT_INITIALIZED. Is there any notification from FltMgr when it is initialized and ready to register FS filters? For now I create worker thread from DriverEntry which periodically tries to register with FltMgr as a workaround.


As far as i know there isn’t any notification from FltMgr that it’s loaded. Other that trying to register from a different thread you could try a reinitialize routine (IoRegisterDriverReinitialization()). I’ve never tried it but as far as i can tell it should work.


>from a different thread you could try a reinitialize routine (IoRegisterDriverReinitialization()).

Isn’t this very routine used by FltMgr to create next frames after the legacy filter is loaded?

Maxim S. Shatskih
Windows DDK MVP

No, I’ve just looked at this recently and frame0 gets created right from


Yes, that IoRegisterDriverReinitialization works fine, thanks.