One Lightroom user seeing this error corrected the problem-
He created a new catalog and imported the most recent, malfunctioning catalog into it. "the new one seems to be working."
I'm getting this same error message but I have no idea how to do what you suggest. Can you please provide a link to some sort of directions?
First check to see that every original image file previewed in the slide-show exists. (A missing image has a '!' on the thumbnail)
The procedure for the new catalog is not difficult- but I do not know if this will work for you!!
1. In Lightroom menu- File > New Catalog (Give it name and location)
2. When the 'new' catalog opens (it will be blank), menu- File > Import from another catalog.
3. choose the name of your 'old' catalog to import. This will become your working catalog.
I tried the "import broke catalog into new one" approach but unfortunately the problem still persists. (Actually was getting worse).
All photos are "online". I am using LR CC 2015.2.1 on W10. It appears on any collection I try to do a slideshow with.
Any thoughts anyone? This error is prohibiting using "Slideshow" altogether.
Update: I contacted LR's helpdesk. The problem does not occur with a newly created admin user. It seems the original user account has a glitch.
I had the same problem but found that my driver for my Graphix card was not correct. Updated the driver and Lightroom Slideshow Preview works. Appears that Lightroom requires a GPU to work.
This j u s t happened to me. Even though my images were visible in the Library & Develop modules, I went back to FILE and 're-imported' my images to the 'Library' this time it worked.
Goodbye Adobe- Lightroom, been fighting this error for 3 days with no product support or useful help. No I am not turning total ownership of my photos over to you for a monthly fee... hello Affinity Photo, very pleased to meet you!