Hi,
I've been getting crashes when I have what seems like a critical mass of mods enabled. They usually seem to crash in core/ore-restore.lua:17 with "attempt to index field '?': a nil value". I've managed narrow the blame to the following combination of mods:

bob's ores
angel's smelting
offshore P.U.M.P.S
GUFT, of course.

mods added with their respective dependencies. I'm asking here since the crash was in your function, but I honestly don't know which of the four is the root cause...

I'm going to assume it's something offshore p.u.m.p.s did because I've never heard of that one, but whatever the cause it's my bug. I'll see if I can figure out what's up tonight and get a fix out. Thank you for narrowing it down so far!

It seems I made one mistake (thought it was a dependency), but you need bob's plates too. Sorry.
If you need a dump of some configs just let me know how to get them, since I did find that some configs crash the ore area too (particularly if you uncheck ore spawning for some mods that aren't loaded), so I don't think I'm running on the default settings by now.

Edit: Narrowed further
Bob's Ores
Bob's Metals, Chemicals and Intermediates
Bob's Library (dependency of above)
Grand Unified Factorio Theory
OSM lib (dependency of below)
Offshore P.U.M.P.S

Since it doesn't crash without bob's, I assume the adjustments pumps does for bob's could be the cause...

If you want to share mod settings, under your Factorio mod installation's mods folder is a "mod-settings.dat" file. Upload that to onedrive or dropbox or whatever. Sharing a save should also work and that'd also include active the mod list (which is the adjacent mod-list.json file), but if it's a game you've been playing for a while those can get large.

I'm not terribly surprised to hear that some combinations of disabling ores breaks it, I thought I got all of those but just found a problem with the Py disable a few versions ago so I'll believe I missed other ones.

Can't get a save under the right conditions, since the game crashes on init (before opening map). During crash, modlist:
{"mods":
[{"name": "base", "enabled": true},
{"name": "boblibrary", "enabled": true},
{"name": "bobores", "enabled": true},
{"name": "bobplates", "enabled": true},
{"name": "grand-unified-factorio-theory", "enabled": true},
{"name": "osm-lib", "enabled": true},
{"name": "P-U-M-P-S", "enabled": true}]}

Here's the config, if you need it. File contains all the mods I have installed but I couldn't find a way to clean it up... https://cdn.discordapp.com/attachments/282134851514007552/934181972417343588/mod-settings.dat

Offshore PUMPS apparently outright deletes Bob's groundwater rather than just deleting its autoplace config (the thing that tells Factorio how to spawn it) like it should. My code then tried to restore the autoplace to the missing resource, which crashed. For now I'm not going to try to work around that to fully restore the groundwater, this is an edge case that I'm not that worried about, but I did fix it so it at least will load safely. If you (or someone else reading this) wants me to try to preserve entire resources like that let me know.

Also it breaks omnimatter too, though I didn't put any effort into figuring out exactly why on that one. Granted I have no idea why you'd attempt that combination normally, but theoretically with GUFT it SHOULD work since it'll let you mix omnimatter and not-omnimatter in whatever combination, so one of those two mods would need to fix that, but it's arguable that either one is wrong so I wouldn't hold my breath.

I also figured out that disabling omnimatter ores without it installed broke it so I fixed that too. The rest look okay.

I'll have a .11 uploaded in a few minutes, probably by the time you read this. If I missed something or you find anything else, let me know.

Thanks, it seems to work now with the large pack I'm trying to start. See you in a few years, I guess :D