XnView Software

If any image is to be saved in JPG format (save as), the bar runs to approx. 99% and the program stops. Nothing more happens.
RAM is then at least 2-3GB.
After terminating the process “guetzli_windows_x86-64.exe” the program can be used. However, no file has been saved.
If the image has already been saved as a JPG and is saved after a change, it works without any problems.

Win10 Pro x64
XnView 1.8.0 64 bit

The processing time for JPG Guetzli is impracticably long except for small images, it was only ever intended for web images.

I have suggested that a warning pop-up be displayed when Guetzli is selected, but not all good suggestions are implemented...

There other much newer formats which produce smaller file sizes than standard JPEG with normal processing times, haven't used them myself yet so can't give their names.

Forget Guetzli and try jpegli. It's fast and produces the best jpeg quality of any compressor I've used so far. And if you use the XYB option, you will receive an even smaller file, but be careful, web programs (e.g. Joomla) have problems with it and distort colors, so be careful when using it on the web.