Had that at the beginning of Java 8 support. I had to delete my installation and completely reinstall CafeTran.
Don't forget to back up all your user files. I'd advice you to create fresh settings. Perhaps you want to make screenshots of the old ones, before deleting CafeTran.app.
After this (one time) replacement, the spinning beach ball never returned when using the file selector.
After updating to the latest Java 1.8.0_111 on macOS Sierra, some web resources could make the app unresponsive when they where loaded at the start resulting in the spinning beach ball. It occurred sporadically. Please update CafeTran to latest build of update 25 (build 2016111404) before the update 26 is released. This issue should be fixed.
If I had one wish I'd've found a way to use El Capitan... or even Windows Vista instead of Sierra.
Best answer: What's wrong with Windows Vista or Win8?
I have a late 2012 Mini that was running some feline thing. I wanted to upgrade to Yosemite or El Cap'n for the dictation and nothing else. First it didn't like the 16 Gig of Patriot Ram, and went bonkers, flicking off suddenly. Replaced that with 8 Gb of RAM blessed and anointed by the Pope of Apple and the elechtronics settled down some. But (spoiler alert!) after 2 years of running smoothly on another Mac mini, this OS is a sudden nightmare kinda like getting into a car wreck. I pity the guys in tech support.
Meanwhile, is there a blog showing how to ditch Sierra for The Cap'n?
HL
The public beta for macOS Sierra is available now: https://beta.apple.com/sp/betaprogram/
You can download it and install it on an external drive to test whether CafeTran will run on macOS Sierra.
Who has time and fun to do this?