Mod crashes the game with error message " Failed to load mods: Error while loading item prototype "spidertron-cannon" (gun): Prototype "spidertron-cannon" registered twice
Modifications: Spidertron Weapon Switcher 1.2.9"
I then have to disable the mod to load my Factorio 1.1 world. I do have Spidertron Extended installed as well as Spidertron Enhancements. Could this be a compatibility issue?

Hello, thanks for the report!

Has this just started happening or have you just changed something in your modlist (added/removed/updated some mods?). From googling the issue it seems that you might have somehow installed the mod twice?? Maybe go to your mod folder and check that there's nothing unusual there?

If you're still stuck please upload your log here so I can see exactly which mods and versions you're using. I've just tested it with Spidertron Enhancements and Extended at it seems to work fine (just as well because I've implemented specific integrations between this and both those mods!).

I think I just found the issue, but I'll have to test it. I have Bob's Warfare mod installed which adds a spidertron with a cannon to the game. Perhaps this is the reason for the weapon to register twice. I'm going to download your mod again and see if I get the same crash. Stay tuned.

Oh yes, bob's warfare also creates an item called 'spidertron-cannon' so you'll have to pick which mod you want to use (until one of us updates to change the internal name, but I can't do that for a few weeks).