I had a strange experience while installing it.
1. It installed fine on my desktop. I used the Ctrl-Button technique to change the default language to English. A warning window opened up saying something like "all features may not work." Most functions worked, but one didn't. I combined many pdf files. The combine part worked, but the program wouldn't save the joint file; that window saying "may not work" kept coming. I clicked on "check upgrade". It upgraded (very quickly) and asked me to reboot. I did. When I restarted the program, everything worked fine.
2. Here's the strange experience: I tried to install the program on my laptop (a slightly older version of Windows 10 64bit. It looked like the install went through all the way. But no changes were made at all to the file system. And, there's no program. I tried three times. Same result. Each time, it takes quite a while, extracting files, installing, etc and finally it says done. But there's nothing to show for it.
I have never had such an experience before. I know all kinds of ways intall would go wrong. But for an install routine to say it has finished and there being nothing on the hard disc!
I find the mystery puzzling. It's an absolutely normal standard laptop, with enough disk space and memory. Everything is flat average about it.