Sorry to hear you're having issues. How do the images look in Develop? Is GPU on?
Thanks for the reply.
The image looks normal in every other module.
It only looks like that when the slideshow is playing.
Yes, the GPU is active.
It only did it to a couple of photos in the slideshow, not every one.
Slideshow uses Library Previews to run, so something is rather odd that's causing it to do that.
I can only suggest trying to turn things on and off to test. Turn off GPU (though it's not used in Slideshow anyway).
Turn off Pan and Tilt.
Restart Lightroom and try again.
I tried both steps as suggested.
Unfortunately that did not fix the problem.
Perhaps deleting and rebuilding the preview folder may help?
Any other suggestions?
Well, I moved the preview folder and let it rebuild the 29 photos from the birthday party.
There are actually 5 of 29 photos that show the error which unfortunately did persist.
The error looks exactly like before.
I'm not sure what else to do. Any other thoughts?
If the previews are fine in Library, then in theory, there's no reason to delete the previews folder. I asked about Develop, because it would show file corruption quicker than anywhere else, and if there was an issue with the file on disk, you'd see it there.
Hi, Mark. I have this problem as well. My current working theory is that this happens when using very large image files in your slideshow. I have slimmed down some of the images and that helped out.
How big are your image files? My smaller files (e.g. under 5 MB) seemed oh. Some (but not all) of my larger image files (e.g. over 10 MB) seemed to exhibit this behavior.
On a side note, I would be careful about installing Lightroom CC 2015.1. If you haven't yet, I would stay away for now. I have been working on a slideshow for this coming weekend and the 2015.1 release has been a bit of a disaster. I am currently trying to figure out how to go back to the original 2015 release (before 2015.1).
let me know if this works out for you!
Hey Ed, thank you for your response.
I shot these images in RAW and then converted them to DNG.
All of the file sizes are between around 18.5 to 23 MB.
The image size doesn't seem to correlate with the problem.
There are plenty of images that are on the larger size that are just fine.
And there are several images that demonstrate the abnormality that are on the smaller end of this spectrum.
This problem was present before updating the program and persisted following the update.
I am hopeful that someone from Adobe will chime in with a suggestion to fix this.
Hi, Mark. I did a little more testing myself and it appears that you are correct - the image size does not seem to be the root cause. In my original runs, it seemed like it, but in my most recent video render, a few of the smaller images had the same issue.
I just did a render in LR 5.7.1 (which I installed for the first time last night). In this case, I did not use a background image nor did I have any music in the show. So far, it looks like it rendered fine. (It's a 27 minute video, so I only spot checked it). So, I will now add the background image and the music and see what happens.
In the mean time, if you figure out any workarounds, please let me know!
Lightroom version: 5.7.1 
License type: Creative Cloud
Operating system: Windows 8.1 Home Premium Edition
Version: 6.3 
Application architecture: x64
System architecture: x64
Logical processor count: 8
Processor speed: 3.5 GHz
Built-in memory: 32719.1 MB
Real memory available to Lightroom: 32719.1 MB
Real memory used by Lightroom: 2069.6 MB (6.3%)
Virtual memory used by Lightroom: 2452.1 MB
Memory cache size: 5481.3 MB
Maximum thread count used by Camera Raw: 4
System DPI setting: 96 DPI
Desktop composition enabled: Yes
Displays: 1) 1920x1200, 2) 1920x1200
Application folder: C:\Program Files\Adobe\Adobe Photoshop Lightroom 5.7.1
Library Path: D:\Projects\Photo\Nat and Nick Wedding Slide Show\LR 5\LR 5.lrcat
Settings Folder: C:\Users\Ed\AppData\Roaming\Adobe\Lightroom
2) Canon Tether Plugin
5) Leica Tether Plugin
6) Nikon Tether Plugin
Config.lua flags: None
Adapter #1: Vendor : 1002
Device : 6811
Subsystem : b041002
Revision : 0
Video Memory : 2027
Adapter #2: Vendor : 1414
Device : 8c
Subsystem : 0
Revision : 0
Video Memory : 0
AudioDeviceName: Speakers (SB Recon3D PCIe)
Renderer: AMD Radeon (TM) R9 200 Series
Still waiting for some help here.
Your optimism is to be commended Mark, but this is a user forum. Sometimes staff drop by, but it's certainly not a given. As this seems to be a bug rather than something that can be worked around, go here: Recently active topics in Photoshop Family about Photoshop Lightroom and report it.
Thanks for the reply.
I had thought that Adobe assisted with troubleshooting in this forum.
Oh well. I will try as you suggested.
Hopefully a fix will be found in the near future.
This bug has been acknowledge by Adobe in the official Adobe feedback forum: Lightroom 6.0 slideshow - images rendered as swapped blocks. Please add your vote and opinion to help ensure that Adobe prioritizes a fix.
Adobe has identified at least one cause of the problem, a bug in AMD's Windows OpenGL driver that LR 6 triggers (but evidently LR 5 does not). When you add your details to that thread, be sure to include the exact model of video card and your platform (Windows / Mac).
Thank you for the update.
I have chimed in at the other forum.
At least they are aware of the issue and are working on it.