OLIunpacker automatically decompress, stacks, reprojects, and derives a cloud mask from Fmask. It requires USGS CRD OLI image products downloaded from USGS Earth Explorer as input. It locates these files in the targz folder in the user-provided scene directory path. For each compressed image file it creates a new temporary folder where compressed images in the targz folder are decompressed to. The compressed CDR product includes L8SR surface reflectance image bands and cloud masks. OLIunpackr decompresses the CDR product, stacks image bands 1-7 and reprojects the image stack. The included Fmask cloud mask is reclassified to include only values 0 and 1 representing obscured and clear-view pixel designations. This means that original values for cloud, cloud shadow, snow, and no observation are all assigned the value 0 while clear land and clear water are assigned the value 1. Fmask reclassication is done to match the MSS cloud mask produced by MSScvm and to allow efficient mask application during the compositing process (miXel). The cloud mask is reprojected in the same way as the corresponding image stack. The final image stack, image ancillary data, and cloud mask are renamed and placed in a subdirectoy to the scene directory called images where they are further divided into folders by year.