I pull up an image that I have been analyzing and half of it is black and the other half is the normal image. Additionally, it seems as though the actual histology has been shifted so the margins no longer align. My data analysis is still there, but I cannot finish analyzing it because I cannot see the histology.
It’s just a guess because your description is sparse (which OS, Java version, image filetype, image size, etc. - open Plugin->Utilities->ImageJ Properties and Image->Show Info) but It could be related to this Java 1.8 bug: