diff --git a/aegisub/libaegisub/common/charset_ucd.cpp b/aegisub/libaegisub/common/charset_ucd.cpp
index 025ca870e..cbaa661a1 100644
--- a/aegisub/libaegisub/common/charset_ucd.cpp
+++ b/aegisub/libaegisub/common/charset_ucd.cpp
@@ -34,7 +34,7 @@ namespace agi {
 
 UCDetect::UCDetect(const std::string &file): nsUniversalDetector(NS_FILTER_ALL) {
 	{
-		std::auto_ptr<std::ifstream> fp(io::Open(file));
+		std::auto_ptr<std::ifstream> fp(io::Open(file, true));
 
 		while (!mDone && !fp->eof()) {
 			char buf[512];