I normally use Denoise v 6.0.1 via Photoshop so never had reason to notice the following until using it in stand alone mode.
I open a tif file, applied a light denoise and go to menu to Save As… and choose a new name and as a tiff format with defaults, then OK. The progress bar at the bottom indicates it’s working and when finished, DeNoise is unceremoniously closed (no message). Checking on the new file though, it doesn’t exist.
Saving as a jpg, leaves DeNoise running & a file written.
Saving as a png crashes DeNoise and no file written.