diff --git a/source/compiler-core/slang-diagnostic-sink.cpp b/source/compiler-core/slang-diagnostic-sink.cpp
index de8bdf52c2..21592b7e5c 100644
--- a/source/compiler-core/slang-diagnostic-sink.cpp
+++ b/source/compiler-core/slang-diagnostic-sink.cpp
@@ -282,12 +282,18 @@ static void _sourceLocationNoteDiagnostic(
         return;
     }
 
-    UnownedStringSlice content = sourceFile->getContent();
-
-    // Make sure the offset is within content.
+    // Check if the source file has actual content available.
     // This is important because it's possible to have a 'SourceFile' that doesn't contain any
     // content (for example when reconstructed via serialization with just line offsets, the actual
     // source text 'content' isn't available).
+    if (!sourceFile->hasContent())
+    {
+        return;
+    }
+
+    UnownedStringSlice content = sourceFile->getContent();
+
+    // Make sure the offset is within content.
     const int offset = sourceView->getRange().getOffset(sourceLoc);
     if (offset < 0 || offset >= content.getLength())
     {
@@ -388,12 +394,18 @@ static void _tokenLengthNoteDiagnostic(
         return;
     }
 
-    UnownedStringSlice content = sourceFile->getContent();
-
-    // Make sure the offset is within content.
+    // Check if the source file has actual content available.
     // This is important because it's possible to have a 'SourceFile' that doesn't contain any
     // content (for example when reconstructed via serialization with just line offsets, the actual
     // source text 'content' isn't available).
+    if (!sourceFile->hasContent())
+    {
+        return;
+    }
+
+    UnownedStringSlice content = sourceFile->getContent();
+
+    // Make sure the offset is within content.
     const int offset = sourceView->getRange().getOffset(sourceLoc);
     if (offset < 0 || offset >= content.getLength())
     {
diff --git a/source/slang/slang-session.cpp b/source/slang/slang-session.cpp
index 6b3338e0ef..14de8a53b4 100644
--- a/source/slang/slang-session.cpp
+++ b/source/slang/slang-session.cpp
@@ -2039,13 +2039,19 @@ SlangResult Linkage::loadSerializedModuleContents(
     //
     SourceLoc serializedModuleLoc;
     {
-        auto sourceFile =
-            sourceManager->findSourceFileByPathRecursively(moduleFilePathInfo.foundPath);
-        if (!sourceFile)
-        {
-            sourceFile = sourceManager->createSourceFileWithString(moduleFilePathInfo, String());
-            sourceManager->addSourceFile(moduleFilePathInfo.getMostUniqueIdentity(), sourceFile);
-        }
+        // For the purposes of diagnostics, we create a source file to represent
+        // the binary module file. We intentionally create this with empty content
+        // to avoid displaying binary data in error messages.
+        //
+        // Note: We do NOT reuse any existing source file for this path, because
+        // an earlier code path (e.g., IncludeSystem::loadFile) may have loaded
+        // the binary module content into a source file, and we don't want to
+        // display that binary data when showing diagnostic source lines.
+        //
+        auto sourceFile = sourceManager->createSourceFileWithString(moduleFilePathInfo, String());
+        sourceManager->addSourceFileIfNotExist(
+            moduleFilePathInfo.getMostUniqueIdentity(),
+            sourceFile);
         auto sourceView =
             sourceManager->createSourceView(sourceFile, &moduleFilePathInfo, SourceLoc());
         serializedModuleLoc = sourceView->getRange().begin;