Created attachment 103317 [details] screenshot I tried a search as shown in the attachment. I have many non-tagged images, but none of them show up in the search. However, all the non-tagged videos do show up in the search. The Not Tagged search seems to work for video files, but not images. In the example, I clicked "Reset" before trying. The only options selected are "Meet All of the following conditions" and "Not Tagged" This is with digikam 5.4.0 beta on OSX El Capitan.
i tried this again today with digikam 5.5.0 on OSX El Capitan. It worked as expected this time. Consider it resolved.