diff --git a/source/detail/serialization/xlsx_consumer.cpp b/source/detail/serialization/xlsx_consumer.cpp
index 2f29e19f..3fdbad1b 100644
--- a/source/detail/serialization/xlsx_consumer.cpp
+++ b/source/detail/serialization/xlsx_consumer.cpp
@@ -1923,13 +1923,15 @@ void xlsx_consumer::read_shared_string_table()
     {
         expect_start_element(qn("spreadsheetml", "si"), xml::content::complex);
         auto rt = read_rich_text(qn("spreadsheetml", "si"));
-        target_.add_shared_string(rt);
+		//by reading in it can happen we have similar strings from modified excel worksheets...
+		//so allow to add duplicates
+        target_.add_shared_string(rt, true);
         expect_end_element(qn("spreadsheetml", "si"));
     }
 
     expect_end_element(qn("spreadsheetml", "sst"));
 
-    if (has_unique_count && unique_count != target_.shared_strings().size())
+    if (has_unique_count && unique_count != target_.shared_strings_by_id().size())
     {
         throw invalid_file("sizes don't match");
     }