diff --git a/src/main/java/org/embeddedt/modernfix/mixin/perf/modern_resourcepacks/PathResourcePackMixin.java b/src/main/java/org/embeddedt/modernfix/mixin/perf/modern_resourcepacks/PathResourcePackMixin.java
index 7d381d4b..d44f572e 100644
--- a/src/main/java/org/embeddedt/modernfix/mixin/perf/modern_resourcepacks/PathResourcePackMixin.java
+++ b/src/main/java/org/embeddedt/modernfix/mixin/perf/modern_resourcepacks/PathResourcePackMixin.java
@@ -10,6 +10,7 @@ import org.apache.commons.lang3.tuple.Triple;
 import org.embeddedt.modernfix.ModernFix;
 import org.embeddedt.modernfix.util.CachedResourcePath;
 import org.embeddedt.modernfix.util.FileUtil;
+import org.embeddedt.modernfix.util.PackTypeHelper;
 import org.spongepowered.asm.mixin.Final;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.Overwrite;
@@ -83,7 +84,8 @@ public abstract class PathResourcePackMixin {
                         rootListingForNamespaces.put(namespace, Collections.emptyList());
                     }
                 }
-                rootListingByNamespaceAndType.put(type, rootListingForNamespaces);
+                if(PackTypeHelper.isVanillaPackType(type))
+                    rootListingByNamespaceAndType.put(type, rootListingForNamespaces);
             }
             this.rootListingByNamespaceAndType = rootListingByNamespaceAndType;
             this.containedPaths = containedPaths;
@@ -107,6 +109,8 @@ public abstract class PathResourcePackMixin {
 
     @Inject(method = "getNamespaces", at = @At("HEAD"), cancellable = true)
     private void useCacheForNamespaces(PackType type, CallbackInfoReturnable<Set<String>> cir) {
+        if(!PackTypeHelper.isVanillaPackType(type))
+            return;
         Set<String> cachedNamespaces;
         synchronized (this.namespacesByType) {
             cachedNamespaces = this.namespacesByType.get(type);
@@ -118,6 +122,8 @@ public abstract class PathResourcePackMixin {
 
     @Inject(method = "getNamespaces", at = @At("TAIL"))
     private void storeCacheForNamespaces(PackType type, CallbackInfoReturnable<Set<String>> cir) {
+        if(!PackTypeHelper.isVanillaPackType(type))
+            return;
         synchronized (this.namespacesByType) {
             this.namespacesByType.put(type, cir.getReturnValue());
         }
@@ -136,6 +142,8 @@ public abstract class PathResourcePackMixin {
     @Inject(method = "getResources", at = @At("HEAD"), cancellable = true)
     public void getResources(PackType type, String resourceNamespace, String pathIn, int maxDepth, Predicate<String> filter, CallbackInfoReturnable<Collection<ResourceLocation>> cir)
     {
+        if(!PackTypeHelper.isVanillaPackType(type))
+            return;
         this.generateResourceCache();
         if(!pathIn.endsWith("/"))
             pathIn = pathIn + "/";
diff --git a/src/main/java/org/embeddedt/modernfix/mixin/perf/modern_resourcepacks/VanillaPackResourcesMixin.java b/src/main/java/org/embeddedt/modernfix/mixin/perf/modern_resourcepacks/VanillaPackResourcesMixin.java
index 9cd8f89f..29ed4023 100644
--- a/src/main/java/org/embeddedt/modernfix/mixin/perf/modern_resourcepacks/VanillaPackResourcesMixin.java
+++ b/src/main/java/org/embeddedt/modernfix/mixin/perf/modern_resourcepacks/VanillaPackResourcesMixin.java
@@ -10,6 +10,7 @@ import net.minecraft.server.packs.metadata.pack.PackMetadataSection;
 import org.apache.commons.lang3.tuple.Pair;
 import org.embeddedt.modernfix.FileWalker;
 import org.embeddedt.modernfix.util.FileUtil;
+import org.embeddedt.modernfix.util.PackTypeHelper;
 import org.spongepowered.asm.mixin.Final;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.Overwrite;
@@ -43,6 +44,8 @@ public class VanillaPackResourcesMixin {
         containedPaths = new HashSet<>();
         Joiner slashJoiner = Joiner.on('/');
         for(PackType type : PackType.values()) {
+            if(!PackTypeHelper.isVanillaPackType(type))
+                continue;
             Path root = ROOT_DIR_BY_TYPE.get(type);
             if(root == null)
                 throw new IllegalStateException("No filesystem for vanilla " + type.name() + " assets");
@@ -72,6 +75,8 @@ public class VanillaPackResourcesMixin {
 
     @Inject(method = "hasResource", at = @At(value = "INVOKE", target = "Ljava/lang/Class;getResource(Ljava/lang/String;)Ljava/net/URL;"), cancellable = true)
     private void useCacheForExistence(PackType type, ResourceLocation location, CallbackInfoReturnable<Boolean> cir) {
+        if(!PackTypeHelper.isVanillaPackType(type))
+            return;
         cir.setReturnValue(containedPaths.contains(type.getDirectory() + "/" + location.getNamespace() + "/" + FileUtil.normalize(location.getPath())));
     }
 
diff --git a/src/main/java/org/embeddedt/modernfix/util/PackTypeHelper.java b/src/main/java/org/embeddedt/modernfix/util/PackTypeHelper.java
new file mode 100644
index 00000000..13a76311
--- /dev/null
+++ b/src/main/java/org/embeddedt/modernfix/util/PackTypeHelper.java
@@ -0,0 +1,9 @@
+package org.embeddedt.modernfix.util;
+
+import net.minecraft.server.packs.PackType;
+
+public class PackTypeHelper {
+    public static boolean isVanillaPackType(PackType type) {
+        return type == PackType.CLIENT_RESOURCES || type == PackType.SERVER_DATA;
+    }
+}