Can't make CurseForge comment, commenting here sorry.

When loading into a pre-existing World (made before simplyswords was added to collection) the game gets stuck on "reading world data" and goes unresponsive.

This is the only ERROR given with "Simply Swords" mentioned. (FULL LOG ATTACHED ASWELL)

latest.log

2025-04-09-7.log.gz

[16:50:10] [Worker-ResourceReload-1/ERROR]:Couldn't parse element loot_tables:simplyswords:grant_book_on_first_join
com.google.gson.JsonSyntaxException: Expected name to be an item, was unknown string 'patchouli:guide_book'
at net.minecraft.util.GsonHelper.m_13866_(GsonHelper.java:145) ~[client-1.20.1-20230612.114412-srg.jar%23504!/:?]
at java.util.Optional.orElseThrow(Unknown Source) ~[?:?]
at net.minecraft.util.GsonHelper.m_13874_(GsonHelper.java:145) ~[client-1.20.1-20230612.114412-srg.jar%23504!/:?]
at net.minecraft.util.GsonHelper.m_13909_(GsonHelper.java:153) ~[client-1.20.1-20230612.114412-srg.jar%23504!/:?]
at net.minecraft.world.level.storage.loot.entries.LootItem$Serializer.m_7267_(LootItem.java:55) ~[client-1.20.1-20230612.114412-srg.jar%23504!/:?]
at net.minecraft.world.level.storage.loot.entries.LootItem$Serializer.m_7267_(LootItem.java:40) ~[client-1.20.1-20230612.114412-srg.jar%23504!/:?]
at net.minecraft.world.level.storage.loot.entries.LootPoolSingletonContainer$Serializer.m_5921_(LootPoolSingletonContainer.java:151) ~[client-1.20.1-20230612.114412-srg.jar%23504!/:?]
at net.minecraft.world.level.storage.loot.entries.LootPoolSingletonContainer$Serializer.m_5921_(LootPoolSingletonContainer.java:129) ~[client-1.20.1-20230612.114412-srg.jar%23504!/:?]
at net.minecraft.world.level.storage.loot.entries.LootPoolEntryContainer$Serializer.m_7561_(LootPoolEntryContainer.java:86) ~[client-1.20.1-20230612.114412-srg.jar%23504!/:?]
at net.minecraft.world.level.storage.loot.entries.LootPoolEntryContainer$Serializer.m_7561_(LootPoolEntryContainer.java:74) ~[client-1.20.1-20230612.114412-srg.jar%23504!/:?]
at net.minecraft.world.level.storage.loot.GsonAdapterFactory$JsonAdapter.deserialize(GsonAdapterFactory.java:102) ~[client-1.20.1-20230612.114412-srg.jar%23504!/:?]
at com.google.gson.internal.bind.TreeTypeAdapter.read(TreeTypeAdapter.java:76) ~[gson-2.10.jar%23107!/:?]
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.read(TypeAdapterRuntimeTypeWrapper.java:40) ~[gson-2.10.jar%23107!/:?]
at com.google.gson.internal.bind.ArrayTypeAdapter.read(ArrayTypeAdapter.java:72) ~[gson-2.10.jar%23107!/:?]
at com.google.gson.Gson.fromJson(Gson.java:1214) ~[gson-2.10.jar%23107!/:?]
at com.google.gson.Gson.fromJson(Gson.java:1319) ~[gson-2.10.jar%23107!/:?]
at com.google.gson.Gson.fromJson(Gson.java:1290) ~[gson-2.10.jar%23107!/:?]
at com.google.gson.internal.bind.TreeTypeAdapter$GsonContextImpl.deserialize(TreeTypeAdapter.java:179) ~[gson-2.10.jar%23107!/:?]
at net.minecraft.util.GsonHelper.m_13808_(GsonHelper.java:463) ~[client-1.20.1-20230612.114412-srg.jar%23504!/:?]
at net.minecraft.util.GsonHelper.m_13836_(GsonHelper.java:471) ~[client-1.20.1-20230612.114412-srg.jar%23504!/:?]
at net.minecraft.world.level.storage.loot.LootPool$Serializer.deserialize(LootPool.java:192) ~[client-1.20.1-20230612.114412-srg.jar%23504!/:?]
at net.minecraft.world.level.storage.loot.LootPool$Serializer.deserialize(LootPool.java:189) ~[client-1.20.1-20230612.114412-srg.jar%23504!/:?]
at com.google.gson.internal.bind.TreeTypeAdapter.read(TreeTypeAdapter.java:76) ~[gson-2.10.jar%23107!/:?]
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.read(TypeAdapterRuntimeTypeWrapper.java:40) ~[gson-2.10.jar%23107!/:?]
at com.google.gson.internal.bind.ArrayTypeAdapter.read(ArrayTypeAdapter.java:72) ~[gson-2.10.jar%23107!/:?]
at com.google.gson.Gson.fromJson(Gson.java:1214) ~[gson-2.10.jar%23107!/:?]
at com.google.gson.Gson.fromJson(Gson.java:1319) ~[gson-2.10.jar%23107!/:?]
at com.google.gson.Gson.fromJson(Gson.java:1290) ~[gson-2.10.jar%23107!/:?]
at com.google.gson.internal.bind.TreeTypeAdapter$GsonContextImpl.deserialize(TreeTypeAdapter.java:179) ~[gson-2.10.jar%23107!/:?]

You have a lot of errors in the log unrelated to Simply Swords, possibly caused by Essential.
Please perform isolation testing with only Simply Swords and it's required dependencies to see if the issues persist. If they do not, then you likely have some mod conflicts in your pack and you will need to determine the cause by process of elimination.

This has already been isolated, none of the other errors are fatal and are expected. It is only when adding Simply Swords to the collection it no longer works.