Paper finding that explicitly welcomed minorities felt less welcome I'm trying to track down a research paper that I have lost the details for. Any help tracking it down would be very, very welcome!

It described an experiment where a US college showed prospective students a promotional video with one of two narration tracks: one which said that all students are welcome; and another where various minority groups were specifically said to be welcome. I seem to recall that the video itself, which showed a variety of students, was the same for both groups.

The results showed that students from those minority groups rated the video that singled out demographic groups as less welcoming. 

The conclusion was that by singling out demographics as needing to be welcomed separately, this made people feel different and therefore less welcome.
I think the description provided (if accurate) should be enough to find the paper, unless it is not available online, or is only available in a different language.  Sometimes authors of books and certain review papers will reference unpublished research, so it may have come up in that context.  Or it may not exist at all.

The results described are in line with what diversity training guides often recommend, for example:


  Do talk about everybody’s differences. Teaching about cultural differences must be inclusive of all people, at all times.
  
  Don’t single out particular groups, such as ‘ethnic groups’.


Unfortunately, such materials rarely provide references to support recommendations.

This area of research falls under "multiculturalism vs colorblindness" - the question of whether it is best to highlight differences between groups, or to ignore them.  A recent review (2018), that also references 3 other recent comprehensive reviews, echoes the findings of over 25 years of research (eg, see earlier review (1993)) that the multicultural approach is generally superior across a wide variety of outcome measures.

That said, there are certainly many ways in which attempts to foster diversity can go wrong, and can be more clearly refined.  Perhaps singling out specific groups, as suggested by some training guides, is one of those pitfalls (for a similar example, see the minority spotlight effect).  It would be interesting to see a study that addresses this question directly.