In this video, I focus on one of the most frustrating problems in ENVI image processing: when FLAASH atmospheric correction fails and throws errors that stop your workflow. I walk you through how I diagnose the issue step-by-step—starting from the error message itself—so you can quickly narrow down whether the problem is sensor/metadata, wrong model choices, or a bad input file setup. The goal is simple: get a clean surface reflectance output without wasting hours repeating the same failed run. I show the practical checks I always do: confirm the sensor and metadata are correct, pick the right atmospheric model, and verify visibility and aerosol parameters so MODTRAN/FLAASH has realistic inputs. I also cover common file-related causes like corrupted ENVI headers, wrong band ordering, incompatible formats, and missing/incorrect radiometric calibration—especially when you’re working across multispectral and hyperspectral datasets. By the end, you’ll have a repeatable troubleshooting checklist and a few prevention tips to reduce FLAASH errors in future projects.