diff --git a/components/fpspreadsheet/examples/other/metadata/demo_metadata.lpr b/components/fpspreadsheet/examples/other/metadata/demo_metadata.lpr
index 50fb7ad07..7ad702e35 100644
--- a/components/fpspreadsheet/examples/other/metadata/demo_metadata.lpr
+++ b/components/fpspreadsheet/examples/other/metadata/demo_metadata.lpr
@@ -58,6 +58,7 @@ end;
 var
   book: TsWorkbook;
   sheet: TsWorksheet;
+  i: Integer;
 begin
   book := TsWorkbook.Create;
   try
@@ -72,6 +73,8 @@ begin
     book.MetaData.Comments.Add('Assign the creation date to the field CreatedAt.');
     book.MetaData.Keywords.Add('Test');
     book.MetaData.Keywords.Add('FPSpreadsheet');
+    book.MetaData.AddCustom('Comparny', 'Disney');
+    book.MetaData.AddCustom('Status', 'finished');
 
     sheet := book.AddWorksheet('Test');
     sheet.WriteText(2, 3, 'abc');
@@ -86,9 +89,9 @@ begin
   book := TsWorkbook.Create;
   try
     // Select one of these
-    book.ReadFromFile('test.ods');
+//    book.ReadFromFile('test.ods');
 //    book.ReadFromFile('test.xlsx');
-//    book.ReadFromFile('test.xml');
+    book.ReadFromFile('test.xml');
     WriteLn('Created by         : ', book.MetaData.CreatedBy);
     WriteLn('Date created       : ', DateTimeToStr(book.MetaData.DateCreated));
     WriteLn('Modified by        : ', book.MetaData.LastModifiedBy);
@@ -96,6 +99,9 @@ begin
     WriteLn('Title              : ', book.MetaData.Title);
     WriteLn('Subject            : ', book.MetaData.Subject);
     WriteLn('Keywords           : ', book.MetaData.Keywords.CommaText);
+    WriteLn('Custom             : ', 'Name':20, 'Value':20);
+    for i := 0 to book.MetaData.Custom.Count-1 do
+      WriteLn('                     ', book.MetaData.Custom.Names[i]:20, book.MetaData.Custom.ValueFromIndex[i]:20);
     WriteLn('Comments: ');
     WriteLn(book.MetaData.Comments.Text);
   finally
diff --git a/components/fpspreadsheet/source/common/fpsopendocument.pas b/components/fpspreadsheet/source/common/fpsopendocument.pas
index 0d658a528..6d2fe7ba4 100644
--- a/components/fpspreadsheet/source/common/fpsopendocument.pas
+++ b/components/fpspreadsheet/source/common/fpsopendocument.pas
@@ -1966,6 +1966,7 @@ var
   book: TsWorkbook;
   nodeName: String;
   s: String;
+  name: String;
 begin
   book := TsWorkbook(FWorkbook);
 
@@ -1992,6 +1993,12 @@ begin
         book.MetaData.Title := s;
       'dc:subject':
         book.Metadata.Subject := s;
+      'meta:user-defined':
+        begin
+          name := GetAttrValue(ANode, 'meta:name');
+          if name <> '' then
+            book.MetaData.AddCustom(name, s);
+        end;
     end;
     ANode := ANode.NextSibling;
   end;
@@ -5911,6 +5918,16 @@ begin
         '<dc:description>%s</dc:description>', [s]));
   end;
 
+  if book.MetaData.Custom.Count > 0 then
+  begin
+    for i := 0 to book.Metadata.Custom.Count-1 do
+      AppendToStream(FSMeta, Format(
+        '<meta:user-defined meta:name="%s">%s</meta:user-defined>', [
+          book.Metadata.Custom.Names[i],
+          book.Metadata.Custom.ValueFromIndex[i]
+        ]));
+  end;
+
   AppendToStream(FSMeta,
       '</office:meta>');
   AppendToStream(FSMeta,
diff --git a/components/fpspreadsheet/source/common/fpstypes.pas b/components/fpspreadsheet/source/common/fpstypes.pas
index 20e6afb0b..447fa00c3 100644
--- a/components/fpspreadsheet/source/common/fpstypes.pas
+++ b/components/fpspreadsheet/source/common/fpstypes.pas
@@ -976,9 +976,12 @@ type
     FSubject: String;
     FComments: TStrings;
     FKeywords: TStrings;
+    FCustom: TStrings;
   public
     constructor Create;
     destructor Destroy; override;
+    function AddCustom(AName, AValue: String): Integer;
+    procedure Clear;
     function IsEmpty: Boolean;
     property CreatedBy: String read FCreatedBy write FCreatedBy;
     property LastModifiedBy: String read FLastModifiedBy write FLastModifiedBy;
@@ -987,6 +990,7 @@ type
     property Subject: String read FSubject write FSubject;
     property Title: String read FTitle write FTitle;
     property Comments: TStrings read FComments write FComments;
+    property Custom: TStrings read FCustom write FCustom;
     property Keywords: TStrings read FKeywords write FKeywords;
   end;
 
@@ -1199,20 +1203,44 @@ begin
   inherited;
   FComments := TStringList.Create;
   FKeywords := TStringList.Create;
+  FCustom := TStringList.Create;
 end;
 
 destructor TsMetaData.Destroy;
 begin
   FComments.Free;
   FKeywords.Free;
+  FCustom.Free;
   inherited;
 end;
 
+procedure TsMetaData.Clear;
+begin
+  FTitle := '';
+  FSubject := '';
+  FCreatedBy := '';
+  FLastModifiedBy := '';
+  FDateCreated := 0;
+  FDateLastModified := 0;
+  FComments.Clear;
+  FKeywords.Clear;
+  FCustom.Clear;
+end;
+
+function TsMetaData.AddCustom(AName, AValue: String): Integer;
+begin
+  Result := FCustom.IndexOf(AName);
+  if result > -1 then
+    FCustom.ValueFromIndex[Result] := AValue
+  else
+    Result := FCustom.Add(AName + '=' + AValue);
+end;
+
 function TsMetaData.IsEmpty: Boolean;
 begin
   Result := (FCreatedBy = '') and (FLastModifiedBy = '') and
     (FTitle = '') and (FSubject = '') and
-    (FComments.Count = 0) and (FKeywords.Count = 0) and
+    (FComments.Count = 0) and (FKeywords.Count = 0) and (FCustom.Count = 0) and
     (FDateCreated = 0) and (FDateLastModified = 0);
 end;
 
diff --git a/components/fpspreadsheet/source/common/xlsxml.pas b/components/fpspreadsheet/source/common/xlsxml.pas
index f43d6540e..f1c4f06b3 100644
--- a/components/fpspreadsheet/source/common/xlsxml.pas
+++ b/components/fpspreadsheet/source/common/xlsxml.pas
@@ -45,6 +45,7 @@ type
     procedure ReadCellProtection(ANode: TDOMNode; var AFormat: TsCellFormat);
     procedure ReadComment(ANode: TDOMNode; AWorksheet: TsBasicWorksheet; ACell: PCell);
     procedure ReadConditionalFormatting(ANode: TDOMNode; AWorksheet: TsBasicWorksheet);
+    procedure ReadCustomDocumentProperties(ANode: TDOMNode);
     procedure ReadDocumentProperties(ANode: TDOMNode);
     procedure ReadExcelWorkbook(ANode: TDOMNode);
     procedure ReadFont(ANode: TDOMNode; var AFormat: TsCellFormat);
@@ -96,6 +97,7 @@ type
     procedure WriteConditionalFormat(AStream: TStream; AWorksheet: TsBasicWorksheet;
       AFormat: TsConditionalFormat);
     procedure WriteConditionalFormatting(AStream: TStream; AWorksheet: TsBasicWorksheet);
+    procedure WriteCustomDocumentProperties(AStream: TStream);
     procedure WriteDocumentProperties(AStream: TStream);
     procedure WriteExcelWorkbook(AStream: TStream);
     procedure WriteNames(AStream: TStream; AWorksheet: TsBasicWorksheet);
@@ -1100,6 +1102,32 @@ begin
   sheet.WriteConditionalCellFormat(range, TsCFCondition(condition), op1, op2, fmtIndex);
 end;
 
+{@@ ----------------------------------------------------------------------------
+  Read the custom meta data fields
+-------------------------------------------------------------------------------}
+procedure TsSpreadExcelXMLReader.ReadCustomDocumentProperties(ANode: TDOMNode);
+var
+  book: TsWorkbook;
+  value: String;
+  nodeName: String;
+begin
+  if ANode = nil then
+    exit;
+
+  book := TsWorkbook(FWorkbook);
+  ANode := ANode.FirstChild;
+  while ANode <> nil do
+  begin
+    nodeName := ANode.NodeName;
+    if nodeName <> '#text' then
+    begin
+      value := GetNodeValue(ANode);
+      book.MetaData.AddCustom(nodeName, value);
+    end;
+    ANode := ANode.NextSibling;
+  end;
+end;
+
 {@@ ----------------------------------------------------------------------------
   Reads the meta data etc.
 -------------------------------------------------------------------------------}
@@ -2069,6 +2097,7 @@ begin
 
     // Read meta data
     ReadDocumentProperties(doc.DocumentElement.FindNode('DocumentProperties'));
+    ReadCustomDocumentProperties(doc.DocumentElement.FindNode('CustomDocumentProperties'));
 
     // Read style list
     ReadStyles(doc.DocumentElement.FindNode('Styles'));
@@ -2680,6 +2709,33 @@ begin
   end;
 end;
 
+procedure TsSpreadExcelXMLWriter.WriteCustomDocumentProperties(AStream: TStream);
+{   <CustomDocumentProperties xmlns="urn:schemas-microsoft-com:office:office">
+      <Comparny dt:dt="string">Disney</Comparny>
+      <Status dt:dt="string">finished</Status>
+     </CustomDocumentProperties> }
+var
+  book: TsWorkbook;
+  i: Integer;
+begin
+  book := TsWorkbook(FWorkbook);
+  if book.MetaData.Custom.Count = 0 then
+    exit;
+
+  AppendToStream(AStream, INDENT1 +
+    '<CustomDocumentProperties xmlns="urn:schemas-microsoft-com:office:office">' + LF);
+
+  for i := 0 to book.MetaData.Custom.Count-1 do
+    AppendToStream(AStream, Format(INDENT2 +
+      '<%0:s dt:dt="string">%1:s</%0:s>' + LF, [
+      book.MetaData.Custom.Names[i],
+      book.MetaData.Custom.ValueFromIndex[i]
+    ]));
+
+  AppendToStream(AStream, INDENT1 +
+    '</CustomDocumentProperties>' + LF);
+end;
+
 procedure TsSpreadExcelXMLWriter.WriteDateTime(AStream: TStream;
   const ARow, ACol: Cardinal; const AValue: TDateTime; ACell: PCell);
 var
@@ -2719,8 +2775,6 @@ begin
 end;
 
 procedure TsSpreadExcelXMLWriter.WriteDocumentProperties(AStream: TStream);
-const
-  LE = LineEnding;
 var
   sTitle: String;
   sSubject: String;
@@ -2733,32 +2787,30 @@ var
 begin
   book := TsWorkbook(FWorkbook);
 
-  if (book.MetaData.Title = '') and
-     (book.MetaData.CreatedBy = '') and (book.MetaData.LastModifiedBy = '') and
-     (book.MetaData.DateCreated <= 0) and (book.MetaData.DateLastModified <= 0) then
+  if book.MetaData.IsEmpty then
   begin
     AppendToStream(AStream, INDENT1 +
-      '<DocumentProperties xmlns="urn:schemas-microsoft-com:office:office" />' + LE);
+      '<DocumentProperties xmlns="urn:schemas-microsoft-com:office:office" />' + LF);
     exit;
   end;
 
   if book.MetaData.Title <> '' then
-    sTitle := '<Title>' + book.MetaData.Title + '</Title>' + LE + INDENT2
+    sTitle := '<Title>' + book.MetaData.Title + '</Title>' + LF + INDENT2
   else
     sTitle := '';
 
   if book.MetaData.Subject <> '' then
-    sSubject := '<Subject>' + book.MetaData.Subject + '</Subject>' + LE + INDENT2
+    sSubject := '<Subject>' + book.MetaData.Subject + '</Subject>' + LF + INDENT2
   else
     sSubject := '';
 
   if book.MetaData.CreatedBy <> '' then
-    sAuthor := '<Author>' + book.MetaData.CreatedBy + '</Author>' + LE + INDENT2
+    sAuthor := '<Author>' + book.MetaData.CreatedBy + '</Author>' + LF + INDENT2
   else
     sAuthor := '';
 
   if book.MetaData.LastModifiedBy <> '' then
-    sLastAuthor := '<LastAuthor>' + book.MetaData.LastModifiedBy + '</LastAuthor>' + LE + INDENT2
+    sLastAuthor := '<LastAuthor>' + book.MetaData.LastModifiedBy + '</LastAuthor>' + LF + INDENT2
   else
     sLastAuthor := '';
 
@@ -2766,7 +2818,7 @@ begin
   if book.MetaData.DateCreated > 0 then begin
     dt := book.MetaData.DateCreated + GetLocalTimeOffset / (24*60);
     sDateCreated := FormatDateTime(ISO8601FormatExtendedUTC, dt);
-    sDateCreated := '<Created>' + sDateCreated + '</Created>' + LE + INDENT2;
+    sDateCreated := '<Created>' + sDateCreated + '</Created>' + LF + INDENT2;
   end else
     sDateCreated := '';
 
@@ -2774,20 +2826,20 @@ begin
   begin
     dt := book.MetaData.DateLastModified + GetLocalTimeOffset / (24*60);
     sDateLastSaved := FormatDateTime(ISO8601FormatExtendedUTC, dt);
-    sDateLastSaved := '<LastSaved>' + sDateLastSaved + '</LastSaved>' + LE + INDENT2;
+    sDateLastSaved := '<LastSaved>' + sDateLastSaved + '</LastSaved>' + LF + INDENT2;
   end else
     sDateLastSaved := '';
 
   AppendToStream(AStream, INDENT1 +
-    '<DocumentProperties xmlns="urn:schemas-microsoft-com:office:office">' + LE + INDENT2 +
+    '<DocumentProperties xmlns="urn:schemas-microsoft-com:office:office">' + LF + INDENT2 +
       sTitle +
       sSubject +
       sAuthor +
       sLastAuthor +
       sDateCreated +
       sDateLastSaved +
-      '<Version>16.00</Version>' + LE + Indent1 +
-    '</DocumentProperties>' + LE
+      '<Version>16.00</Version>' + LF + INDENT1 +
+    '</DocumentProperties>' + LF
   );
 end;
 
@@ -3397,9 +3449,11 @@ begin
     '          xmlns:o="urn:schemas-microsoft-com:office:office"' + LF +
     '          xmlns:x="urn:schemas-microsoft-com:office:excel"' + LF +
     '          xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet"' + LF +
+    '          xmlns:dt="uuid:C2F41010-65B3-11d1-A29F-00AA00C14882"' + LF +
     '          xmlns:html="http://www.w3.org/TR/REC-html40">' + LF);
 
   WriteDocumentProperties(AStream);
+  WriteCustomDocumentProperties(AStream);
   WriteOfficeDocumentSettings(AStream);
   WriteExcelWorkbook(AStream);
   WriteStyles(AStream);
diff --git a/components/fpspreadsheet/source/common/xlsxooxml.pas b/components/fpspreadsheet/source/common/xlsxooxml.pas
index a9702d7ee..0292176b4 100644
--- a/components/fpspreadsheet/source/common/xlsxooxml.pas
+++ b/components/fpspreadsheet/source/common/xlsxooxml.pas
@@ -173,6 +173,7 @@ type
     procedure WriteComments(AWorksheet: TsBasicWorksheet);
     procedure WriteConditionalFormat(AStream: TStream; AFormat: TsConditionalFormat; var APriority: Integer);
     procedure WriteConditionalFormats(AStream: TStream; AWorksheet: TsBasicWorksheet);
+    procedure WriteCustomMetaData(AStream: TStream);
     procedure WriteDefinedNames(AStream: TStream);
     procedure WriteDifferentialFormat(AStream: TStream; AFormat: PsCellFormat);
     procedure WriteDifferentialFormats(AStream: TStream);
@@ -217,6 +218,7 @@ type
     FSWorkbook: TStream;
     FSWorkbookRels: TStream;
     FSMetaData: TStream;
+    FSCustomMetaData: TStream;
     FSStyles: TStream;
     FSSharedStrings: TStream;
     FSSharedStrings_complete: TStream;
@@ -307,6 +309,7 @@ const
      OOXML_PATH_XL_THEME           = 'xl/theme/theme1.xml';
      OOXML_PATH_XL_MEDIA           = 'xl/media/';
      OOXML_PATH_DOCPROPS_CORE      = 'docProps/core.xml';
+     OOXML_PATH_DOCPROPS_CUSTOM    = 'docProps/custom.xml';
 
      { OOXML schemas constants }
      SCHEMAS_TYPES        = 'http://schemas.openxmlformats.org/package/2006/content-types';
@@ -314,6 +317,7 @@ const
      SCHEMAS_DOC_RELS     = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships';
      SCHEMAS_DOCUMENT     = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument';
      SCHEMAS_META_CORE    = 'http://schemas.openxmlformats.org/package/2006/relationships/metadata/core-properties';
+     SCHEMAS_META_CUSTOM  = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/custom-properties';
      SCHEMAS_WORKSHEET    = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/worksheet';
      SCHEMAS_STYLES       = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/styles';
      SCHEMAS_STRINGS      = 'http://schemas.openxmlformats.org/officeDocument/2006/relationships/sharedStrings';
@@ -330,6 +334,7 @@ const
      MIME_RELS            = 'application/vnd.openxmlformats-package.relationships+xml';
      MIME_OFFICEDOCUMENT  = 'application/vnd.openxmlformats-officedocument';
      MIME_CORE            = 'application/vnd.openxmlformats-package.core-properties+xml';
+     MIME_CUSTOM          = 'application/vnd.openxmlformats-officedocument.custom-properties+xml';
      MIME_SPREADML        = MIME_OFFICEDOCUMENT + '.spreadsheetml';
      MIME_SHEET           = MIME_SPREADML + '.sheet.main+xml';
      MIME_WORKSHEET       = MIME_SPREADML + '.worksheet+xml';
@@ -2695,9 +2700,11 @@ end;
 
 procedure TsSpreadOOXMLReader.ReadMetaData(ANode: TDOMNode);
 var
+  childNode: TDOMNode;
   nodeName: string;
   book: TsWorkbook;
   s: String;
+  name: String;
   dt: TDateTime;
   fs: TFormatSettings;
 begin
@@ -2714,6 +2721,7 @@ begin
     nodeName := ANode.NodeName;
     s := GetNodeValue(ANode);
     case nodeName of
+      // These fields are from "core.xml"
       'dc:title':
         book.MetaData.Title := s;
       'dc:subject':
@@ -2740,6 +2748,21 @@ begin
       'dcterms:modified':
         if s <> '' then
           book.MetaData.DateLastModified :=ISO8601StrToDateTime(s);
+
+      // This field is from "custom.xml"
+      'property':
+        begin
+          name := GetAttrValue(ANode, 'name');
+          childNode := ANode.Firstchild;
+          while childNode <> nil do
+          begin
+            nodeName := childNode.NodeName;
+            s := GetNodeValue(childNode);
+            if (s <> '') then
+              book.MetaData.AddCustom(name, s);
+            break;
+          end;
+        end;
     end;
     ANode := ANode.NextSibling;
   end;
@@ -3798,6 +3821,18 @@ begin
     finally
       XMLStream.Free;
     end;
+    // custom meta data
+    XMLStream := CreateXMLStream;
+    try
+      if UnzipToStream(AStream, OOXML_PATH_DOCPROPS_CUSTOM, XMLStream) then
+      begin
+        ReadXMLStream(Doc, XMLStream);
+        ReadMetaData(Doc.DocumentElement);
+        FreeAndNil(Doc);
+      end;
+    finally
+      XMLStream.Free;
+    end;
 
   finally
     FreeAndNil(Doc);
@@ -4516,6 +4551,37 @@ begin
   end;
 end;
 
+procedure TsSpreadOOXMLWriter.WriteCustomMetaData(AStream: TStream);
+var
+  book: TsWorkbook;
+  i: Integer;
+  id: Integer;
+begin
+  book := TsWorkbook(FWorkbook);
+  if book.MetaData.Custom.Count = 0 then
+    exit;
+
+  AppendToStream(AStream,
+    '<Properties xmlns="http://schemas.openxmlformats.org/officeDocument/2006/custom-properties" ' +
+      'xmlns:vt="http://schemas.openxmlformats.org/officeDocument/2006/docPropsVTypes">');
+
+  id := 2;
+  for i := 0 to book.MetaData.Custom.Count-1 do
+  begin
+    AppendToStream(AStream, Format(
+      '<property fmtid="{D5CDD505-2E9C-101B-9397-08002B2CF9AE}" pid="%d" name="%s">' +
+        '<vt:lpwstr>%s</vt:lpwstr>' +
+      '</property>', [
+      id, book.MetaData.Custom.Names[i],
+      book.MetaData.Custom.ValueFromIndex[i]
+    ]));
+    inc(id);
+  end;
+
+  AppendToStream(AStream,
+    '</Properties>');
+end;
+
 procedure TsSpreadOOXMLWriter.WriteDimension(AStream: TStream;
   AWorksheet: TsBasicWorksheet);
 var
@@ -6084,18 +6150,29 @@ begin
 
   { --- meta data ---- }
   WriteMetaData(FSMetaData);
+  WriteCustomMetaData(FSCustomMetaData);
 
   { --- _rels/.rels --- }
   AppendToStream(FSRelsRels,
     XML_HEADER + LineEnding);
+
   AppendToStream(FSRelsRels, Format(
-    '<Relationships xmlns="%s">' + LineEnding, [SCHEMAS_RELS]));
-  AppendToStream(FSRelsRels, Format(
-      '<Relationship Id="rId2" Target="docProps/core.xml" Type="%s" />' + LineEnding,
-      [SCHEMAS_META_CORE]));
+    '<Relationships xmlns="%s">' + LineEnding,
+      [SCHEMAS_RELS]));
+
   AppendToStream(FSRelsRels, Format(
       '<Relationship Id="rId1" Target="xl/workbook.xml" Type="%s" />' + LineEnding,
       [SCHEMAS_DOCUMENT]));
+
+  AppendToStream(FSRelsRels, Format(
+      '<Relationship Id="rId2" Target="docProps/core.xml" Type="%s" />' + LineEnding,
+      [SCHEMAS_META_CORE]));
+
+  if TsWorkbook(FWorkbook).MetaData.Custom.Count > 0 then
+    AppendToStream(FSRelsRels, Format(
+      '<Relationship Id="rId3" Target="docProps/custom.xml" Type="%s" />' + LineEnding,
+      [SCHEMAS_META_CUSTOM]));
+
   AppendToStream(FSRelsRels,
     '</Relationships>');
 
@@ -6378,6 +6455,10 @@ begin
   AppendToStream(FSContentTypes,
       '<Override PartName="/docProps/core.xml" ContentType="' + MIME_CORE + '" />');
 
+  if book.MetaData.Custom.Count > 0 then
+    AppendToStream(FSContentTypes,
+      '<Override PartName="/docProps/custom.xml" ContentType="' + MIME_CUSTOM + '" />');
+
   AppendToStream(FSContentTypes,
     '</Types>');
 end;
@@ -6808,6 +6889,7 @@ begin
   FSSharedStrings := CreateTempStream(FWorkbook, 'fpsSS');
   FSSharedStrings_complete := CreateTempStream(FWorkbook, 'fpsSSC');
   FSMetaData := CreateTempStream(FWorkbook, 'fpsMETA');
+  FSCustomMetaData := CreateTempStream(FWorkbook, 'fpsCM');
   {
   if boFileStream in FWorkbook.Options then
   begin
@@ -6848,6 +6930,7 @@ procedure TsSpreadOOXMLWriter.DestroyStreams;
 var
   stream: TStream;
 begin
+  DestroyTempStream(FSCustomMetaData);
   DestroyTempStream(FSMetaData);
   DestroyTempStream(FSContentTypes);
   DestroyTempStream(FSRelsRels);
@@ -6897,6 +6980,7 @@ begin
   ResetStream(FSStyles);
   ResetStream(FSSharedStrings_complete);
   ResetStream(FSMetaData);
+  ResetStream(FSCustomMetaData);
   for i:=0 to High(FSSheets) do ResetStream(FSSheets[i]);
   for i:=0 to High(FSSheetRels) do ResetStream(FSSheetRels[i]);
   for i:=0 to High(FSComments) do ResetStream(FSComments[i]);
@@ -6964,6 +7048,8 @@ begin
     if FSSharedStrings_complete.Size > 0 then
       FZip.Entries.AddFileEntry(FSSharedStrings_complete, OOXML_PATH_XL_STRINGS);
     FZip.Entries.AddFileEntry(FSMetaData, OOXML_PATH_DOCPROPS_CORE);
+    if TsWorkbook(FWorkbook).MetaData.Custom.Count > 0 then
+      FZip.Entries.AddFileEntry(FSCustomMetaData, OOXML_PATH_DOCPROPS_CUSTOM);
 
     // Write embedded images
     WriteMedia(FZip);