From 19ea96a3ac977b56c4d3d24333eb201d7a9ba155 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20K=C3=A4llman?= <jan.kallman@epplussoftware.com>
Date: Tue, 19 May 2026 08:08:13 +0200
Subject: [PATCH] Fix for issue #2349

---
 src/EPPlus/ExcelPackageAsync.cs               |  4 +-
 .../Longrunning Tests/LongRunningTests.cs     | 41 +++++++++++++++++++
 2 files changed, 43 insertions(+), 2 deletions(-)

diff --git a/src/EPPlus/ExcelPackageAsync.cs b/src/EPPlus/ExcelPackageAsync.cs
index 85264e5c87..16975717e6 100644
--- a/src/EPPlus/ExcelPackageAsync.cs
+++ b/src/EPPlus/ExcelPackageAsync.cs
@@ -175,8 +175,8 @@ private async Task LoadAsync(Stream input, Stream output, string Password, Cance
 				}
                 finally
                 {
-                    ms.Dispose();
-				}
+                    //ms.Dispose();   //Don't dispose the stream as it is used as the base for the ZipPackage when having 2GB streams or larger. It will be disposed when the package is disposed or saved.
+                }
             }
             //Clear the workbook so that it gets reinitialized next time
             this._workbook = null;
diff --git a/src/EPPlusTest/Longrunning Tests/LongRunningTests.cs b/src/EPPlusTest/Longrunning Tests/LongRunningTests.cs
index 62996b8d17..785081dc4d 100644
--- a/src/EPPlusTest/Longrunning Tests/LongRunningTests.cs	
+++ b/src/EPPlusTest/Longrunning Tests/LongRunningTests.cs	
@@ -159,6 +159,47 @@ public void PerformanceIssueGetAsByteArray()
                 SaveWorkbook("PivotTest_calculated_columns.xlsx", p);
             }
         }
+        [TestMethod]
+        public void PerformanceIssueLoadAndSave()
+        {
+            using (var p = OpenTemplatePackage("LargeWorkbookTemplate.xlsx"))
+            {
+                /* Raw Data Sheet only */
+                ExcelWorksheet ws = p.Workbook.Worksheets[0];  // second sheet
+
+                p.Workbook.Calculate();
+                SaveWorkbook("LargeWBSave.xlsx", p);
+            }
+        }
+        [TestMethod]
+        public void PerformanceIssueLoadAndSaveSync()
+        {
+            using (var p = new ExcelPackage())
+            {
+                var file = GetTemplateFile("LargeWorkbookTemplate.xlsx");
+                p.Load(new FileStream(file.FullName, FileMode.Open));
+                /* Raw Data Sheet only */
+                ExcelWorksheet ws = p.Workbook.Worksheets[0];  // second sheet
+
+                p.Workbook.Calculate();
+            }
+        }
+
+
+        [TestMethod]
+        public async Task PerformanceIssueLoadAndSaveAsync()
+        {
+            using (var p = new ExcelPackage())
+            {
+                var file = GetTemplateFile("LargeWorkbookTemplate.xlsx");
+                await p.LoadAsync(file);
+                /* Raw Data Sheet only */
+                ExcelWorksheet ws = p.Workbook.Worksheets[0];  // second sheet
+
+                p.Workbook.Calculate();                
+            }
+        }
+
         #endregion
         #region HtmlExport
         [TestMethod]