It is very hard to say without more information. This is not a known problem in ENVI.It would probably be most efficient for you to work directly with Exelis VIS Tech Support or your local distributor to track down what is going wrong. You can contact Exelis VIS Tech Support at support@exelisvis.com or (303) 413-3920. This forum is intended mainly as a way for different users in the ENVI community to talk to each other, and it is not the best way to receive technical support. The information that would be helpful for Tech Support to know includes: - What version of ENVI you are working in - The header file (.hdr) for the Hyperion data - How the file was orthorectified - What operating system, including 32-bit or 64-bit, and which version of the OS, you are running ENVI on when this happens Peg Exelis VIS