diff --git a/mp/src/tier1/strtools.cpp b/mp/src/tier1/strtools.cpp
index 2c5f72fa..105c8ef5 100644
--- a/mp/src/tier1/strtools.cpp
+++ b/mp/src/tier1/strtools.cpp
@@ -1411,7 +1411,7 @@ int _V_UCS2ToUnicode( const ucs2 *pUCS2, wchar_t *pUnicode, int cubDestSizeInByt
 	size_t nMaxUTF8 = cubDestSizeInBytes;
 	char *pIn = (char *)pUCS2;
 	char *pOut = (char *)pUnicode;
-	if ( conv_t > 0 )
+	if ( conv_t && conv_t != ((iconv_t)-1) )
 	{
 		cchResult = iconv( conv_t, &pIn, &nLenUnicde, &pOut, &nMaxUTF8 );
 		iconv_close( conv_t );
@@ -1451,7 +1451,7 @@ int _V_UnicodeToUCS2( const wchar_t *pUnicode, int cubSrcInBytes, char *pUCS2, i
 	size_t nMaxUCS2 = cubDestSizeInBytes;
 	char *pIn = (char*)pUnicode;
 	char *pOut = pUCS2;
-	if ( conv_t > 0 )
+	if ( conv_t && conv_t != ((iconv_t)-1) )
 	{
 		cchResult = iconv( conv_t, &pIn, &nLenUnicde, &pOut, &nMaxUCS2 );
 		iconv_close( conv_t );
@@ -1499,7 +1499,7 @@ int _V_UCS2ToUTF8( const ucs2 *pUCS2, char *pUTF8, int cubDestSizeInBytes )
 	size_t nMaxUTF8 = cubDestSizeInBytes - 1;
 	char *pIn = (char *)pUCS2;
 	char *pOut = (char *)pUTF8;
-	if ( conv_t > 0 )
+	if ( conv_t && conv_t != ((iconv_t)-1) )
 	{
 		const size_t nBytesToWrite = nMaxUTF8;
 		cchResult = iconv( conv_t, &pIn, &nLenUnicde, &pOut, &nMaxUTF8 );
@@ -1544,7 +1544,7 @@ int _V_UTF8ToUCS2( const char *pUTF8, int cubSrcInBytes, ucs2 *pUCS2, int cubDes
 	size_t nMaxUTF8 = cubDestSizeInBytes;
 	char *pIn = (char *)pUTF8;
 	char *pOut = (char *)pUCS2;
-	if ( conv_t > 0 )
+	if ( conv_t && conv_t != ((iconv_t)-1) )
 	{
 		cchResult = iconv( conv_t, &pIn, &nLenUnicde, &pOut, &nMaxUTF8 );
 		iconv_close( conv_t );