How to find master slides being used?

Good idea!  Between marking a big, red, circle on the master, and changing the master as soon as I import, upcoming master management should be easier.  Thanks for the tips!

Ahhh!!!  I just found my problem!    I have a slide, which has three layers.  The layout master was changed for the slide, but the layers did not adopt the change.  I'm not sure if this is a bug. But, I am unable to change the master for the layers.  I guess my only option may be to delete and recreate them (?). 

It looks like I don't have a blank feedback layer.  If I look at the layout style for the base layer, I see the master I want.  If I make the layer active, then look at the layout of this slide again, I get an obscure master, that I usually see in quiz feedback.  Where would I define a blank feedback later?  I am about to start an afternoon of meetings, but hope this is an easy fix when I return. Again, thanks for the direction. 

I used Geert's solution, but in the opposite way. My presentation had 3-4 masters, so it was easier to change the background color on the master I wanted to KEEP to green. Then I looked through my presentation for any slides that weren't green and updated those. Once every slide was green, I deleted the unused masters and updated the "keeper" master back to its original color.

I think this method may help in some cases described above because anything that's not green stands out and you can easily take a closer look at the details (e.g., a white rectangle covers the whole slide).

So thank you all for your suggestions.  I have done all of these things.  I have looked at each and every slide in my presentation (several times) and now again with the big red X and there are still several slides masters showing  as being used that are not showing on any slide.  (says one is on 16 slides!  I couldn't have missed ALL of them)  Is there a way to 'hide' entire slides?  I discovered that unused questions banks had slide in them that had to be updated but even having done that there are still slides I can't 'find'.  Any ideas or suggestions would be helpful.

Thanks!

@wendy - I haven't been staying current with this discussion recently, so maybe someone already suggested this.  But, I found that when I was unable to tell where a master slide was being used, it ended up being in some obscure location, like a quiz question, or layer. It might even be in a place that will almost never be seen (such as an incorrect feedback for an easy-to-answer quiz question). 

Glad to see some tips here on how to find that 1 elusive slide layout using the wrong slide master! Thanks to those who posted.

This (multiple versions of the same slide master) is still a huge annoyance. Every time I import a slide into a project, it brings the entire slide master with it, even though the slides are using the same slide master template/names. It may not affect functionality, but it can affect consistency if someone imports a slide from an old layout that has been updated elsewhere. I've added my 2c with a feature request, but since the first post is 9 years old.... not holding my breath.

Hello all. I have been having the same issue everyone here has been talking about for the past 8 years, but now in my most recent project, it has expanded into the Feedback Master! I may be the only Storyline developer who didn't know that all slide layers use the Feedback Master blank layout by default. So when I wanted to clean up my master slides, I could not delete several feedback masters because some layer somewhere in my course was using that master's blank layout. That elusive message "Layout Blank being used by 1 slide" is killing me! ha ha

Articulate 360 - Storyline: Slide Layers Use the Feedback Master Blank Layout by Default - Articulate Support

The feature that would have been helpful for 12 years now is still missing in 2024.