Error:

Failed to load mod "mini-machines": Cannot Copy, invalid prototype
stack traceback:
[C]: in function 'error'
stdlib/stdlib/data/data.lua:190: in function 'copy'
mini-machines/func.lua:293: in function 'miniaturize'
mini-machines/data-final-fixes.lua:28: in main chunk
18.680 Loading mod core 0.0.0 (data.lua)
18.830 Checksum for core: 1964106968
18.912 Error ModManager.cpp:1471: Error in assignID, recipe-category with name 'crafting' does not exist.

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I'm on Factorio version 0.18.18 and no errors.. any potential big mods you might be using? Something appears to be massively modifying base game recipe categories.

On 0.18.18, I can confirm you are incompatible with Krastorio 2 at this time. I disabled only Krastorio 2, and it loaded.

Alright, I've added preliminary compatibility with Krastorio2. The game will load with just mini and Kras2, but I haven't tested with any other additions. Hopefully fixed as of v7.1.4

With my mod set, it has not been fixed.
Output:
52.746 Loading mod mini-machines 7.1.4 (data-final-fixes.lua)
52.755 Script @stdlib/stdlib/data/data.lua:39: Item mini-assembler-0 does not exist. [stdlib/stdlib/data/data.lua:490 in Item, stdlib/stdlib/data/recipe.lua:47 in format, stdlib/stdlib/data/recipe.lua:62 in get_difficulties, stdlib/stdlib/data/recipe.lua:153 in replace_ingredient, @mini-machines/func.lua:306 in miniaturize, @mini-machines/data-final-fixes.lua:10 in ???]
52.759 Script @stdlib/stdlib/data/data.lua:39: Data item/electric-furnace-1 does not exist. [stdlib/stdlib/data/data.lua:490 in Data, @mini-machines/func.lua:290 in miniaturize, @mini-machines/data-final-fixes.lua:38 in ???]
52.759 Script @stdlib/stdlib/data/data.lua:39: Data furnace/electric-furnace does not exist. [stdlib/stdlib/data/data.lua:490 in Data, @mini-machines/func.lua:303 in miniaturize, @mini-machines/data-final-fixes.lua:38 in ???]
53.074 Error ModManager.cpp:1471: Failed to load mod "mini-machines": Cannot Copy, invalid prototype
stack traceback:
[C]: in function 'error'
stdlib/stdlib/data/data.lua:190: in function 'copy'
mini-machines/func.lua:303: in function 'miniaturize'
mini-machines/data-final-fixes.lua:38: in main chunk
53.076 Loading mod core 0.0.0 (data.lua)
53.537 Checksum for core: 2893833208
53.667 Error ModManager.cpp:1471: Error in assignID, recipe-category with name 'crafting' does not exist.

Source: default (utility-sprites).

I also use electric furnaces, that may be an issue
Edit: With Krastorio 2 disabled, factorio loaded with mini machines. 0.18.18 with 7.1.4
Narrowed down to Bob's Assembling mod and Electric Furnaces with Krastorio 2 and Mini Machines.
--I have Krastorio 2 and Mini Machines enabled and the game will load. When I enabled either (or both) Bob's Assembling Mod and/or Electric Furnaces, I error out. (With Krastorio 2 and Mini Machines still enabled)
Please note I can have Electric Furnaces, Bob's Assembling, and Krastorio 2 enabled without Mini Machines just fine.

I was wondering why you had a completely different error compared to me, when I was initially fixing.

I'm preeetty sure you're not supposed to be using bobs with Krastorio 2. You're not really supposed to be using any other big mods apart from Krastorio 2. Doesn't it already add higher tier electric furnaces? I barely understood the reasoning for having bobs and electric furnaces when somebody else had an issue using both of them with this mod.

Either they would add different versions of the same machine, or they would override each other's crafting speed, recipes, unlocks, etc. Or it could just straight break the balancing for one of the mods in question. There's just no point to such a clusterf, is there?

There is some support for bobs individual modules (explicitly for bobs enemies). For example, I have bob's assembly but that's it. (It adds assembly machines 4, 5, 6). Oil Refineries and Centrifuges 2 and 3. Those tiers that are not present in Krastorio 2. Electric Furnaces makes electric versions of the bottom two tiers of furnaces (or what I love is a stone/steel furnace (electric) in a 2x2. Krastorio 2 doesn't do that either. TLDR; I get electric furnaces and higher tier assembly machines that Krastorio 2 doesn't offer. They all work fine together until I enable mini machines.
Edit: Bob's adds Electric Furnaces 2 and 3. But not electric versions of stone and steel furnaces.

Hmmm... looking back on it, I suppose they could technically all be used together. I thought bob's assembling machines also added mining drills (which would conflict with Kras2's advanced drills).

There might be some issue with my detection logic or something else then, if nothing else is being overriden.

Oookay, not sure what versions of bobs assembling machines, Kras2, or electric furnaces you're using, but with just the current Bob Assembly v0.18.4, Bob Functions v0.18.7, Electric Furnaces v2.4.7, and Krastorio2 v0.9.11, game crashes while loading with "attempt to index 'electric-furnace' (a nil value)"

This crash makes sense, because another thing Kras2 does is remove the vanilla electric furnace from the furnace category, and adding it to the assembling-machine category. Note, this is BEFORE attempting to add mini machines to the mix.

I was using everything you were, except Bob Functions on 18.6. However, on 18.6, I disabled everything down to those 4 and got the same issue. Then updated to 18.7, same issue. However, go figure, I re-enabled the Aircraft 1.7.1 mod and the game loaded. So I loaded with B.Assembly 18.4, B.Functions 18.7, E.Furnaces 2.4.7, K2 9.11, Aircraft 1.7.1, Base 18.18. Enabling mini machines now gives the
stdlib/stdlib/data/data.lua:190: in function 'copy'
mini-machines/func.lua:303: in function 'miniaturize'
mini-machines/data-final-fixes.lua:38: in main chunk

Give that a try. I hate enabling a mod to fix an error but yeah.... And thank you for trying to resolve this problem. I have always loved your mod since I started using it in 0.14. Again, thank you, it is appreciated.

That's incredibly weird; I don't see a single reference to furnaces in the Aircraft mod, and there still doesn't seem to be a furnace type version of that entity, but for some reason, it loads up fine...

Which causes a mismatch error for my mod, because the t1 electric furnace is an assembling machine type of entity, but the t2 and t3 versions of the furnace are still furnace type entities. This puts them in very different sections of the data.... I might just have to do a manual conversion of the t2 and t3 furnaces, same way Kras2 does to t1 furnace.

Alright, fixed as of v7.1.5