For Blue Iris 4.7.3 and newer
Blue Iris 4.7.3 and newer includes UI3 as its default web interface. Several supporting files previously included in UI2 releases are now included with Blue Iris, so those files are no longer included with UI2 from version 0.20.0 onward.
If your Blue Iris version is 4.7.2.4 or older, please install an older UI2 release.