Index: Application/Ringtoets/src/Application.Ringtoets.Storage/StorageSqLite.cs
===================================================================
diff -u -rae6f0c6b534ca650e160ae6d9c0bc90369d25c68 -rfd1d509e55af9d6961d8765545261f47cb61ee4d
--- Application/Ringtoets/src/Application.Ringtoets.Storage/StorageSqLite.cs	(.../StorageSqLite.cs)	(revision ae6f0c6b534ca650e160ae6d9c0bc90369d25c68)
+++ Application/Ringtoets/src/Application.Ringtoets.Storage/StorageSqLite.cs	(.../StorageSqLite.cs)	(revision fd1d509e55af9d6961d8765545261f47cb61ee4d)
@@ -204,6 +204,12 @@
             }
         }
 
+        public void CloseProject()
+        {
+            filePath = null;
+            connectionString = null;
+        }
+
         public bool HasChanges(Project project)
         {
             if (string.IsNullOrWhiteSpace(connectionString))
Index: Application/Ringtoets/test/Application.Ringtoets.Storage.Test/StorageSqLiteTest.cs
===================================================================
diff -u -rbc9552772d4e6a6bd786dfcaef808da1964e8c53 -rfd1d509e55af9d6961d8765545261f47cb61ee4d
--- Application/Ringtoets/test/Application.Ringtoets.Storage.Test/StorageSqLiteTest.cs	(.../StorageSqLiteTest.cs)	(revision bc9552772d4e6a6bd786dfcaef808da1964e8c53)
+++ Application/Ringtoets/test/Application.Ringtoets.Storage.Test/StorageSqLiteTest.cs	(.../StorageSqLiteTest.cs)	(revision fd1d509e55af9d6961d8765545261f47cb61ee4d)
@@ -551,6 +551,33 @@
         }
 
         [Test]
+        public void HasChanges_ValidProjectLoadedAndThenClosed_ReturnsTrue()
+        {
+            // Setup
+            StorageSqLite storageSqLite = new StorageSqLite();
+            Project storedProject = new Project();
+
+            FileDisposeHelper fileDisposeHelper = new FileDisposeHelper(tempRingtoetsFile);
+            try
+            {
+                SqLiteDatabaseHelper.CreateValidRingtoetsDatabase(tempRingtoetsFile, storedProject);
+                Project loadedProject = storageSqLite.LoadProject(tempRingtoetsFile);
+                storageSqLite.CloseProject();
+
+                // Call
+                bool hasChanges = storageSqLite.HasChanges(loadedProject);
+
+                // Assert
+                Assert.IsTrue(hasChanges);
+            }
+            finally
+            {
+                CallGarbageCollector();
+                fileDisposeHelper.Dispose();
+            }
+        }
+
+        [Test]
         public void HasChanges_ValidProjectLoadedWithUnaffectedChange_ReturnsFalse()
         {
             // Setup
Index: Core/Common/src/Core.Common.Base/Storage/IStoreProject.cs
===================================================================
diff -u -r78144c676f04f1b9c94f6256b3e764cf527f378e -rfd1d509e55af9d6961d8765545261f47cb61ee4d
--- Core/Common/src/Core.Common.Base/Storage/IStoreProject.cs	(.../IStoreProject.cs)	(revision 78144c676f04f1b9c94f6256b3e764cf527f378e)
+++ Core/Common/src/Core.Common.Base/Storage/IStoreProject.cs	(.../IStoreProject.cs)	(revision fd1d509e55af9d6961d8765545261f47cb61ee4d)
@@ -88,6 +88,11 @@
         Project LoadProject(string connectionArguments);
 
         /// <summary>
+        /// Removes the connection to a database that has been made previously.
+        /// </summary>
+        void CloseProject();
+
+        /// <summary>
         /// Checks if <paramref name="project"/> differs from the last saved or loaded <see cref="Project"/>, if any.
         /// </summary>
         /// <param name="project">The <see cref="Project"/> to save.</param>
Index: Core/Common/src/Core.Common.Gui/Commands/StorageCommandHandler.cs
===================================================================
diff -u -rb45253e05c4d283273a39672c5ca8aaf1b398d71 -rfd1d509e55af9d6961d8765545261f47cb61ee4d
--- Core/Common/src/Core.Common.Gui/Commands/StorageCommandHandler.cs	(.../StorageCommandHandler.cs)	(revision b45253e05c4d283273a39672c5ca8aaf1b398d71)
+++ Core/Common/src/Core.Common.Gui/Commands/StorageCommandHandler.cs	(.../StorageCommandHandler.cs)	(revision fd1d509e55af9d6961d8765545261f47cb61ee4d)
@@ -162,6 +162,7 @@
 
             projectOwner.Project = null;
             projectOwner.ProjectFilePath = "";
+            projectPersistor.CloseProject();
             applicationSelection.Selection = null;
 
             mainWindowController.RefreshGui();
Index: Core/Common/test/Core.Common.Gui.Test/Commands/StorageCommandHandlerTest.cs
===================================================================
diff -u -r78144c676f04f1b9c94f6256b3e764cf527f378e -rfd1d509e55af9d6961d8765545261f47cb61ee4d
--- Core/Common/test/Core.Common.Gui.Test/Commands/StorageCommandHandlerTest.cs	(.../StorageCommandHandlerTest.cs)	(revision 78144c676f04f1b9c94f6256b3e764cf527f378e)
+++ Core/Common/test/Core.Common.Gui.Test/Commands/StorageCommandHandlerTest.cs	(.../StorageCommandHandlerTest.cs)	(revision fd1d509e55af9d6961d8765545261f47cb61ee4d)
@@ -133,6 +133,7 @@
             viewCommands.Expect(g => g.RemoveAllViewsForItem(projectMock));
 
             var projectStorage = mocks.Stub<IStoreProject>();
+            projectStorage.Expect(ps => ps.CloseProject());
 
             var projectOwner = mocks.Stub<IProjectOwner>();
             projectOwner.Project = projectMock;
@@ -456,6 +457,7 @@
             var projectStorage = mocks.Stub<IStoreProject>();
             projectStorage.Stub(ps => ps.LoadProject(pathToSomeInvalidFile))
                           .Return(loadedProject);
+            projectStorage.Stub(ps => ps.CloseProject());
             var applicationSelection = mocks.Stub<IApplicationSelection>();
             applicationSelection.Selection = originalProject;