diff --git a/src/main/java/net/fabricmc/loom/configuration/accesswidener/ModAccessWidenerEntry.java b/src/main/java/net/fabricmc/loom/configuration/accesswidener/ModAccessWidenerEntry.java
index e8e083b1..5559c077 100644
--- a/src/main/java/net/fabricmc/loom/configuration/accesswidener/ModAccessWidenerEntry.java
+++ b/src/main/java/net/fabricmc/loom/configuration/accesswidener/ModAccessWidenerEntry.java
@@ -96,7 +96,7 @@ public record ModAccessWidenerEntry(FabricModJson mod, String path, ModEnvironme
 		final ClassTweakerReader.Header header = ClassTweakerReader.readHeader(data);
 
 		if (!header.getNamespace().equals(MappingsNamespace.OFFICIAL.toString())) {
-			throw new IOException("Expected official namespace for access widener entry, found: " + header.getNamespace());
+			throw new IOException("Expected official namespace for access widener entry, found: " + header.getNamespace() + " in mod: " + mod.getId());
 		}
 
 		var reader = ClassTweakerReader.create(visitor);
diff --git a/src/main/java/net/fabricmc/loom/configuration/processors/MinecraftJarProcessorManager.java b/src/main/java/net/fabricmc/loom/configuration/processors/MinecraftJarProcessorManager.java
index c41e8e30..44cbd024 100644
--- a/src/main/java/net/fabricmc/loom/configuration/processors/MinecraftJarProcessorManager.java
+++ b/src/main/java/net/fabricmc/loom/configuration/processors/MinecraftJarProcessorManager.java
@@ -145,7 +145,7 @@ public final class MinecraftJarProcessorManager {
 			try {
 				entry.processJar(jar, context);
 			} catch (IOException e) {
-				throw new IOException("Failed to process jar when running jar processor: %s".formatted(entry.name()), e);
+				throw new IOException("Failed to process jar when running jar processor: %s - %s".formatted(entry.name(), e.getMessage()), e);
 			}
 		}
 	}