Why is Photos App putting my photos in a random oder when "creating" a slideshow. I spent a lot of time creating an album and then putting my photos in a particular order. I have done this many times over the years without this problem
MacBook Pro 15″, macOS 10.13
It will depend on the system version and the theme you are using.
When you are using a theme with more than one photo on each slide, Photos will rearrange the photos to fill the templates. To ensure, that the photos will not be rearranged, use only the basic themes with only one photo per slide, Classic or Ken Burns.
On the older system versions - OS X 10.10.3 to macOS 10.15 the following strategy helped to preserve the sequence of the photos in the album, when creating a slideshow from an album, see this link: How to turn an Album into a Slideshow and… - Apple Community
On the more recently system versions I have not found any reliable method. I am keeping my slideshows short, with only as many photos I can see in the filmstrip at once. That makes it easier to rearrange them by dragging the photos around.
It will depend on the system version and the theme you are using.
When you are using a theme with more than one photo on each slide, Photos will rearrange the photos to fill the templates. To ensure, that the photos will not be rearranged, use only the basic themes with only one photo per slide, Classic or Ken Burns.
On the older system versions - OS X 10.10.3 to macOS 10.15 the following strategy helped to preserve the sequence of the photos in the album, when creating a slideshow from an album, see this link: How to turn an Album into a Slideshow and… - Apple Community
On the more recently system versions I have not found any reliable method. I am keeping my slideshows short, with only as many photos I can see in the filmstrip at once. That makes it easier to rearrange them by dragging the photos around.
The order of Photos in a slideshow
