I am running WebODM in Firefox on a linux machine with 32gb RAM and an i5-6400.
I am stitching a small sections of up to 350 images using the default settings. This runs to completion -
Postprocessing: done (•̀ᴗ•́)و!
and I can see the ortho thumbnail on the right hand side ..but underneath I have the text "An orthophoto could not be generated. To generate one, make sure GPS information is embedded in the EXIF tags of your images, or use a Ground Control Points (GCP) file."
Reloading WebODM puts everything back to normal and I can download the assets as expected.