When you scan technologies to remove recipe unlocks for various remotes, this error shows up if they're not the last unlock due to removing the entry while still iterating. Should be fixed by just returning after you've found what you want to remove.

Fixed for 0.7.0 (i think)

Thanks for the quick fix, got another error in 0.7.1 when used with Artillery Bombardment Remote. Moving the icon_size assignment inside the if/else tool.icon block fixed it for me.

Error while loading shortcut prototype "artillery-bombardment-remote" (shortcut): Key "width" not found in property tree at ROOT.shortcut.artillery-bombardment-remote.icon

Thanks for the report, I'll look into it

I get this error in 0.7.4:

1.692 Loading mod Shortcuts 0.7.4 (data-updates.lua)
1.693 Error ModManager.cpp:1321: Failed to load mod "Shortcuts": Shortcuts/data-updates.lua:27: attempt to index field '?' (a nil value)
stack traceback:
Shortcuts/data-updates.lua:27: in function 'hide_the_remote'
Shortcuts/data-updates.lua:39: in main chunk

list of mods loaded:

0.220 Loading mod core 0.0.0 (data.lua)
0.299 Loading mod base 0.17.59 (data.lua)
0.477 Loading mod SmartTrains 4.0.4 (data.lua)
0.559 Loading mod what-is-it-really-used-for 1.4.3 (data.lua)
0.637 Loading mod BlueprintExtensions 0.4.5 (data.lua)
0.716 Loading mod Bottleneck 0.10.4 (data.lua)
0.792 Loading mod even-distribution 0.3.10 (data.lua)
0.870 Loading mod EvoGUI 0.4.401 (data.lua)
0.950 Loading mod helmod 0.8.12 (data.lua)
1.034 Loading mod LSlib 2019.7.25 (data.lua)
1.118 Loading mod MoreLogisticsSlots 1.4.1 (data.lua)
1.197 Loading mod nicefill 0.1.16 (data.lua)
1.276 Loading mod QoL-TempStations 0.3.3 (data.lua)
1.357 Loading mod TrainDriver_A16_fix 0.17.0 (data.lua)
1.439 Loading mod VehicleSnap 1.17.3 (data.lua)
1.519 Loading mod trainConstructionSite 0.1.9 (data.lua)

Also - is this related ?:

1.817 Error ModManager.cpp:1321: Error in assignID, recipe-category with name 'crafting' does not exist.

Source: default (utility-sprites).