Every single time a Rubia menu simulation comes up, the game stalls (literally everything stops moving, and I can't interact with the menus / settings), and I get a popup from the OS asking me if I want to kill Factorio since it's unresponsive. If I just wait another 20 seconds or so, the menu simulation loads just fine, and things continue until another Rubia menu simulation returns and the same thing happens again.

Some things to note:

• I was on vacation last week, so the last time I played was roughly on the 8th of August. I was not experiencing this behavior before I left for vacation. Notably, it seems like the menu simulations were added while I was away, which is why I'm currently assuming that Rubia is the culprit.
• I'm running Ubuntu and not Windows, so I don't know if this could be affecting the performance in menu simulations, but I will say that I don't notice this in any other menu simulations that come from other mods (Shattered Planet's menu simulations, for example, seem to work fine).

I'd hate to ask for an option to remove the menu simulations since I love watching them. Any idea what could be going on here?

This is not normal behavior. I don't encounter any such lag spike. Could you confirm if you see this behavior with only Rubia (and its dependents) enabled?

For reference, the menu simulations are just supposed to open a specific save file contained in the mod and play it. This is the same way main menu simulations work for normal factorio.

Speaking with some other modders, the most likely issue is that you have a separate mod installed that causes this to happen. I’d need a save file/modlist to diagnose further.
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EDIT: It’s been a week. I’ve niether replicated the issue nor heard back answers to any of my questions. So I’m closing this as abandoned.

Sorry, it took me a while to action this, mostly because I have way too many mods and the idea of un-checking mods 100+ times didn't sound very fun to me lol.

Anyway - just went through the motions of disabling everything and only enabling Rubia. Relaunched the game and waited until a Rubia simulation came up (took forever until I saw the first one) and can confirm that I can't recreate this with just Rubia + its dependents enabled. Unfortunately I don't really relish the idea of enabling mods one by one until I figure it out, and honestly I don't want to put that on you to deal with going through my save to figure out what might be causing it. I'll just deal with it - thanks for taking the report seriously though!

Thanks. You at least confirmed that it is a mod incompatibility, and not a hardware issue.

If you do come back to test, please unpack the Rubia zip, and uncomment this line in menu-simulations.lua. Uncommenting this line of code makes the menu simulation always pick a Rubia menu simulation.

Okay so I was bored this morning and decided to take a crack at it - thank you for calling out that line, it made testing this much more bearable.

In a save where only Rubia + its dependents were installed, I started enabling mods until I found the culprit: somehow, it is being caused by Color Coded Pipes. If I have only that mod installed + Rubia, the Rubia menu simulations start taking forever to load, just like I described in my first comment. Mod link: https://mods.factorio.com/mod/color-coded-pipes

Genuinely no idea why that would be causing an issue, but it's not mission-critical or anything so I'll disable it for now. I'll go report this in that mod's discussion board.

Asher, RSeding, and I figured it out. Asher's Color-Coded-Pipes mod has 34,000 different migrations in it. I have a gigantic blueprint library from playing a shitload of Factorio that somehow got into the file. So everytime you open one of my menu simulations, factorio would manually go through 2 years of everything I ever made, and run 34k different entity migrations, one at a time. We're working it out, but this is mostly an issue with color-coded-pipes.

Fixed in v0.69.111.
Also Asher fixed his own incompat issue in his own mod.
Thanks for hunting down the issue.

Great to hear, thanks for sorting that out!