I usually try to open up 10 images from LR to retouch in PS. But it usually only opens up 9 or 8. I can almost always guess that image #4 will not open into LR. Is this a bug?? Is there any way to fix this?
Thanks for reaching out. That's strange; I don't think I've seen this issue before.
It sounds like you have installed the latest version of Photoshop (23.5) and Lightroom (5.5). You confirm this by going to Help > System Info in either one. What are the file formats you are working on? Is it just image number 4 (which can be any random image) that fails to open? Do you see any error messages?
Please try to open, first three and then five images from Lightroom to retouch in Photoshop and share both the outcomes with us.
Are you working with the preview files of the actual images in Lightroom?