Failed to Register Dimension for ID (Dimension ID Conflict)

What the log looks like

java\.lang\.IllegalArgumentException: Failed to register dimension for id -?\d+, One is already registered
at net\.minecraftforge\.common\.DimensionManager\.registerDimension\(DimensionManager\.java:

How to fix it

1. Check the line right above the error (`LoaderExceptionModCrash: Caught exception from ...`) to confirm which mod failed to register its dimension.
2. If Applied Energistics 2 (`appliedenergistics2`) is listed, navigate to your Minecraft directory and open `config/AppliedEnergistics2/AppliedEnergistics2.cfg` in a text editor.
3. Find the line `I:storageDimensionID=2` (or whichever ID is shown in your crash log) and change the number to an unused integer, such as `4711`.
4. If another mod is shown in the stack trace instead of Applied Energistics 2, open that mod's `.cfg` file in your `config` folder and change its dimension ID setting to a unique number.
5. Save the edited config file and start the game again (if playing an existing world, always change the ID of the newly added mod rather than a dimension you have already visited).

Check your own log