diff --git a/src/java/org/apache/poi/hpsf/MutableProperty.java b/src/java/org/apache/poi/hpsf/MutableProperty.java
index 1aa603a4a..e80644b19 100644
--- a/src/java/org/apache/poi/hpsf/MutableProperty.java
+++ b/src/java/org/apache/poi/hpsf/MutableProperty.java
@@ -108,6 +108,11 @@ public class MutableProperty extends Property
     {
         int length = 0;
         long variantType = getType();
+
+        /* Ensure that wide strings are written if the codepage is Unicode. */
+        if (codepage == Constants.CP_UNICODE && variantType == Variant.VT_LPSTR)
+            variantType = Variant.VT_LPWSTR;
+
         length += TypeWriter.writeUIntToStream(out, variantType);
         length += VariantSupport.write(out, variantType, getValue(), codepage);
         return length;