It seems that something went wrong when accessing to the database where the preview are stored.
The simpliest way to fix this issue is : 1/ Close PTP 2/ Delete the cache file that is next to your project file. If your project if "myProject.kpt" then delete "myProject.cache" 3/ Re-start PTP and load "myProject.kpt"
1/ Is it possible for you to send us one of your scenes images ? We want to know if it comes from a specific image format which support may have changed between the 2 versions. Send it to contact@kolor.com and tell in your mail that the mail is for me.
2/ Just a stupid question, did you close PTP before deleting the cache file?
It's strange, you said it worked before the update to the 2.5 version .
I checked with 2.3.2 version, and got the issue too with your psd file .
A bug is opened on our side, and our image processing engineers will try to find why your psd files do not work.
By the way, the preview of your psd file is not displayed too in XnView software. So the issue is probably due to a bad or unrecognised format in your psd file.
here is what i always did in the past. Render the final as *.exr , do post processing in photoshop - merge all layers and set it to 8bit It always worked in the past, this is the first time that i have this issue.