I fiddlefarted with some settings, and I got this message. I don't remember what settings I changed. What do I need to give you to figure out how to fix this?

Failed to load mods: Cycle in technology tree detected.

planet-discovery-arcanyx
-> s6x-voidcraft
-> s6x-void-science-pack
-> s6x-void-hydro
-> s6x-void-flux
-> s6x-void-runestone
-> s6x-prismite-crystal
-> rocket-silo
-> space-platform
-> space-science-pack
-> space-platform-thruster
-> planet-discovery-arcanyx

I'd need to know the settings you changed. I can't (or at least am not going to bother to) investigate the problem without that.

Strangeness appears to be happening. Here is the information as I learned it.

When I posted this initial bug report, I was getting the error message when only Arcanyx+Dependencies was turned on. This meant I couldn't actually get to my settings to look at what I had changed.

Later, with Arcanyx turned off but Iridescent Industry turned on, I turned on Safe Integration.

After reading your response, I decided to try gain. The error message is gone now. I guess Safe Integration has fixed my problem? So I can actually get to my settings to tell you what I changed. Due dilligence suggests I should do that.

Arcanyx
Prismite on Nauvis: On
Mythril Required for Nuclear: Off

Iridescent Industry
Safe Integration: On (Was off when I got the error message)

I don't understand why changing only Prismite on Nauvis and Mythril Required for Nuclear would break my ability to load the mod.

It isn't anything you did wrong. It's just a combination of settings that I must have broken somewhere along the line. It should be fixed now!