diff --git a/ClosedXML/ClosedXML/ClosedXML.sln b/ClosedXML/ClosedXML/ClosedXML.sln
index 00bd435..9a36446 100644
--- a/ClosedXML/ClosedXML/ClosedXML.sln
+++ b/ClosedXML/ClosedXML/ClosedXML.sln
@@ -57,8 +57,8 @@
 		{BD5E6BFE-E837-4A35-BCA9-39667D873A20}.Release|Any CPU.Build.0 = Release|Any CPU
 		{BD5E6BFE-E837-4A35-BCA9-39667D873A20}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
 		{BD5E6BFE-E837-4A35-BCA9-39667D873A20}.Release|Mixed Platforms.Build.0 = Release|Any CPU
-		{BD5E6BFE-E837-4A35-BCA9-39667D873A20}.Release|x86.ActiveCfg = Release|x64
-		{BD5E6BFE-E837-4A35-BCA9-39667D873A20}.Release|x86.Build.0 = Release|x64
+		{BD5E6BFE-E837-4A35-BCA9-39667D873A20}.Release|x86.ActiveCfg = Release|Any CPU
+		{BD5E6BFE-E837-4A35-BCA9-39667D873A20}.Release|x86.Build.0 = Release|Any CPU
 		{38B882F0-E6F2-45C5-9BE9-CDC27FBEB4AB}.Debug|Any CPU.ActiveCfg = Debug|x86
 		{38B882F0-E6F2-45C5-9BE9-CDC27FBEB4AB}.Debug|Mixed Platforms.ActiveCfg = Debug|x86
 		{38B882F0-E6F2-45C5-9BE9-CDC27FBEB4AB}.Debug|Mixed Platforms.Build.0 = Debug|x86
@@ -89,8 +89,8 @@
 		{5F43B12B-A900-40C6-9924-A0C0B032F791}.Release|Any CPU.Build.0 = Release|Any CPU
 		{5F43B12B-A900-40C6-9924-A0C0B032F791}.Release|Mixed Platforms.ActiveCfg = Release|Any CPU
 		{5F43B12B-A900-40C6-9924-A0C0B032F791}.Release|Mixed Platforms.Build.0 = Release|Any CPU
-		{5F43B12B-A900-40C6-9924-A0C0B032F791}.Release|x86.ActiveCfg = Release|x64
-		{5F43B12B-A900-40C6-9924-A0C0B032F791}.Release|x86.Build.0 = Release|x64
+		{5F43B12B-A900-40C6-9924-A0C0B032F791}.Release|x86.ActiveCfg = Release|Any CPU
+		{5F43B12B-A900-40C6-9924-A0C0B032F791}.Release|x86.Build.0 = Release|Any CPU
 		{E005997D-B192-461F-AA3E-44007A33A3DF}.Debug|Any CPU.ActiveCfg = Debug|x86
 		{E005997D-B192-461F-AA3E-44007A33A3DF}.Debug|Mixed Platforms.ActiveCfg = Debug|x86
 		{E005997D-B192-461F-AA3E-44007A33A3DF}.Debug|Mixed Platforms.Build.0 = Debug|x86
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/PageSetup/IXLPageSetup.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/PageSetup/IXLPageSetup.cs
index 3ad8f3f..955d5fc 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/PageSetup/IXLPageSetup.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/PageSetup/IXLPageSetup.cs
@@ -151,11 +151,11 @@
         /// <summary>
         /// Gets or sets the horizontal dpi for printing the worksheet.
         /// </summary>
-        Int32 HorizontalDpi { get; set; }
+        UInt32 HorizontalDpi { get; set; }
         /// <summary>
         /// Gets or sets the vertical dpi for printing the worksheet.
         /// </summary>
-        Int32 VerticalDpi { get; set; }
+        UInt32 VerticalDpi { get; set; }
         /// <summary>
         /// Gets or sets the page number that will begin the printout.
         /// <para>For example, the first page of your printout could be numbered page 5.</para>
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/PageSetup/XLPageSetup.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/PageSetup/XLPageSetup.cs
index 4c8df9a..c5a9761 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/PageSetup/XLPageSetup.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/PageSetup/XLPageSetup.cs
@@ -95,8 +95,8 @@
 
         public XLPageOrientation PageOrientation { get; set; }
         public XLPaperSize PaperSize { get; set; }
-        public Int32 HorizontalDpi { get; set; }
-        public Int32 VerticalDpi { get; set; }
+        public UInt32 HorizontalDpi { get; set; }
+        public UInt32 VerticalDpi { get; set; }
         public Int32 FirstPageNumber { get; set; }
         public Boolean CenterHorizontally { get; set; }
         public Boolean CenterVertically { get; set; }
diff --git a/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorkbook_Load.cs b/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorkbook_Load.cs
index 37dc69f..854efb9 100644
--- a/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorkbook_Load.cs
+++ b/ClosedXML/ClosedXML/ClosedXML/Excel/XLWorkbook_Load.cs
@@ -186,7 +186,7 @@
                     if (row.Collapsed != null && row.Collapsed)
                         xlRow.Collapse();
 
-                    if (row.OutlineLevel != null)
+                    if (row.OutlineLevel != null && row.OutlineLevel > 0)
                         xlRow.OutlineLevel = row.OutlineLevel;
 
                     if (row.CustomFormat != null)
@@ -559,8 +559,8 @@
                     ws.PageSetup.ShowComments = showCommentsValues.Single(sc => sc.Value == pageSetup.CellComments).Key;
                 if (pageSetup.Errors != null)
                     ws.PageSetup.PrintErrorValue = printErrorValues.Single(p => p.Value == pageSetup.Errors).Key;
-                if (pageSetup.HorizontalDpi != null) ws.PageSetup.HorizontalDpi = Int32.Parse(pageSetup.HorizontalDpi.InnerText);
-                if (pageSetup.VerticalDpi != null) ws.PageSetup.VerticalDpi = Int32.Parse(pageSetup.VerticalDpi.InnerText);
+                if (pageSetup.HorizontalDpi != null) ws.PageSetup.HorizontalDpi = pageSetup.HorizontalDpi.Value;
+                if (pageSetup.VerticalDpi != null) ws.PageSetup.VerticalDpi = pageSetup.VerticalDpi.Value;
                 if (pageSetup.FirstPageNumber != null) ws.PageSetup.FirstPageNumber = Int32.Parse(pageSetup.FirstPageNumber.InnerText);
             }
         }
diff --git a/ClosedXML/ClosedXML/ClosedXML_Sandbox/Program.cs b/ClosedXML/ClosedXML/ClosedXML_Sandbox/Program.cs
index 81d2ee6..2b1d0a9 100644
--- a/ClosedXML/ClosedXML/ClosedXML_Sandbox/Program.cs
+++ b/ClosedXML/ClosedXML/ClosedXML_Sandbox/Program.cs
@@ -15,14 +15,10 @@
 
         static void Main(string[] args)
         {
-            var wb = new XLWorkbook();
-            var ws = wb.Worksheets.Add("New");
-            var dataValidation = ws.Range("A1:B2").DataValidation;
-            dataValidation.WholeNumber.Between(1, 5);
-            dataValidation.ErrorStyle = XLErrorStyle.Warning;
-            dataValidation.ErrorTitle = "Number out of range";
-            dataValidation.ErrorMessage = "Please enter a number between 1 and 5";
-            wb.SaveAs(@"C:\Excel Files\ForTesting\Sandbox.xlsx");
+            var wb = new XLWorkbook(@"c:\Excel Files\ForTesting\Issue_6237.xlsx");
+
+            
+            wb.SaveAs(@"C:\Excel Files\ForTesting\Issue_6237_Saved.xlsx");
         }