Please consider image formats limitations, when exporting large scale orthomosaic from Metashape Professional:
TIFF format doesn't allow to save files larger than 4GB.
JPEG format export is limited by 65535 pixels for any side of the image.
To avoid the format limitation issues you can:
- reduce the export resolution (m/pix) to fit the format limitations,
- use "Split in blocks" feature in the Export Orthomosaic dialog in order to export the orthomosaic in tiled blocks,
- use BigTIFF option for TIFF format export.