If the data was created in your version of Photoshop - then Photoshop would read it.
But if you created the PSD in another application, Photoshop may not be able to read all the data that the other application stored.
That message is informing you about data that came from other applications, or newer versions of Photoshop that added data that your version cannot read.
Thank you for the info. I only have one version of Photoshop on my computer. The one I created the images with won't open them. However, I did have a version of Lightroom on my computer that I removed today. It was newer than my version of Photoshop. I am hoping that without Lightroom on my computer I will not have any more problems. (cross all my fingers) The images that are corrupted are missing data. The Metadata is missing and the layers are missing from the files. If the metadata is missing they won't open at all and if the layers are missing they will open up flattened, some of them are corrupted with data and color switched every which way in the image.