diff --git a/src/document/renderer.c b/src/document/renderer.c
index 58db6d95..07e53bfe 100644
--- a/src/document/renderer.c
+++ b/src/document/renderer.c
@@ -205,7 +205,6 @@ render_encoded_document(struct cache_entry *cached, struct document *document)
 {
 	struct uri *uri = cached->uri;
 	enum stream_encoding encoding = ENCODING_NONE;
-	unsigned char *extension;
 	struct fragment *fragment = get_cache_fragment(cached);
 	struct string buffer = INIT_STRING("", 0);
 
@@ -216,23 +215,26 @@ render_encoded_document(struct cache_entry *cached, struct document *document)
 		buffer.length = fragment->length;
 	}
 
-	extension = get_extension_from_uri(uri);
-	if (extension) {
-		encoding = guess_encoding(extension);
-		mem_free(extension);
-	}
+	if (uri->protocol != PROTOCOL_FILE) {
+		unsigned char *extension = get_extension_from_uri(uri);
 
-	if (encoding != ENCODING_NONE) {
-		int length = 0;
-		unsigned char *source;
+		if (extension) {
+			encoding = guess_encoding(extension);
+			mem_free(extension);
+		}
 
-		source = decode_encoded_buffer(encoding, buffer.source,
+		if (encoding != ENCODING_NONE) {
+			int length = 0;
+			unsigned char *source;
+
+			source = decode_encoded_buffer(encoding, buffer.source,
 					       buffer.length, &length);
-		if (source) {
-			buffer.source = source;
-			buffer.length = length;
-		} else {
-			encoding = ENCODING_NONE;
+			if (source) {
+				buffer.source = source;
+				buffer.length = length;
+			} else {
+				encoding = ENCODING_NONE;
+			}
 		}
 	}