diff --git a/src/common/strconv.cpp b/src/common/strconv.cpp
index c3191201c4..3102294183 100644
--- a/src/common/strconv.cpp
+++ b/src/common/strconv.cpp
@@ -488,7 +488,12 @@ wxMBConv::cWC2MB(const wchar_t *inBuff, size_t inLen, size_t *outLen) const
         // the input is not
         wxCharBuffer buf(dstLen + nulLen - 1);
         memset(buf.data() + dstLen, 0, nulLen);
-        if ( FromWChar(buf.data(), dstLen, inBuff, inLen) != wxCONV_FAILED )
+
+        // Notice that return value of the call to FromWChar() here may be
+        // different from the one above as it could have overestimated the
+        // space needed, while what we get here is the exact length.
+        dstLen = FromWChar(buf.data(), dstLen, inBuff, inLen);
+        if ( dstLen != wxCONV_FAILED )
         {
             if ( outLen )
             {