diff --git a/src/org/labkey/test/components/Component.java b/src/org/labkey/test/components/Component.java
index 121cf23249..386ed6f99a 100644
--- a/src/org/labkey/test/components/Component.java
+++ b/src/org/labkey/test/components/Component.java
@@ -16,6 +16,7 @@
 package org.labkey.test.components;
 
 import org.apache.commons.lang3.NotImplementedException;
+import org.jetbrains.annotations.NotNull;
 import org.labkey.test.Locator;
 import org.labkey.test.selenium.RefindingWebElement;
 import org.labkey.test.util.TestLogger;
@@ -27,6 +28,7 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 import java.util.Optional;
 import java.util.function.Function;
 
@@ -43,13 +45,13 @@ public String toString()
     }
 
     @Override
-    public WebElement findElement(By by)
+    public @NotNull WebElement findElement(@NotNull By by)
     {
         return getComponentElement().findElement(by);
     }
 
     @Override
-    public List<WebElement> findElements(By by)
+    public @NotNull List<WebElement> findElements(@NotNull By by)
     {
         return getComponentElement().findElements(by);
     }
@@ -69,8 +71,9 @@ protected EC elementCache()
                 // Pass if element doesn't exist. Might be checking if component is visible.
             }
 
-            _elementCache = newElementCache();
+            _elementCache = Objects.requireNonNull(newElementCache());
             waitForReady();
+            Objects.requireNonNull(_elementCache, "waitForReady() cleared the element cache");
         }
         return _elementCache;
     }
@@ -103,13 +106,13 @@ protected ElementCache()
         }
 
         @Override
-        public List<WebElement> findElements(By by)
+        public @NotNull List<WebElement> findElements(@NotNull By by)
         {
             return getComponentElement().findElements(by);
         }
 
         @Override
-        public WebElement findElement(By by)
+        public @NotNull WebElement findElement(@NotNull By by)
         {
             return getComponentElement().findElement(by);
         }
diff --git a/src/org/labkey/test/tests/InlineImagesListTest.java b/src/org/labkey/test/tests/InlineImagesListTest.java
index 05c82e15d2..056a9b6d85 100644
--- a/src/org/labkey/test/tests/InlineImagesListTest.java
+++ b/src/org/labkey/test/tests/InlineImagesListTest.java
@@ -28,6 +28,9 @@
 import org.labkey.test.TestTimeoutException;
 import org.labkey.test.WebTestHelper;
 import org.labkey.test.categories.Daily;
+import org.labkey.test.components.list.ManageListsGrid;
+import org.labkey.test.pages.ImportDataPage;
+import org.labkey.test.pages.list.BeginPage;
 import org.labkey.test.pages.list.EditListDefinitionPage;
 import org.labkey.test.params.FieldDefinition;
 import org.labkey.test.params.FieldDefinition.ColumnType;
@@ -35,6 +38,7 @@
 import org.labkey.test.util.DataRegionTable;
 import org.labkey.test.util.ExcelHelper;
 import org.labkey.test.util.TestDataGenerator;
+import org.labkey.test.util.data.TestDataUtils;
 import org.openqa.selenium.By;
 import org.openqa.selenium.support.ui.ExpectedConditions;
 
@@ -44,6 +48,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.NoSuchElementException;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
@@ -52,6 +57,9 @@
 @BaseWebDriverTest.ClassTimeout(minutes = 5)
 public class InlineImagesListTest extends BaseWebDriverTest
 {
+    private final static String PROJECT_NAME = "Inline Images List Test Project";
+    private final static String IMPORT_PROJECT_NAME = "Inline Images List Import Test Project";
+
     protected final static String LIST_NAME = TestDataGenerator.randomDomainName("InlineImagesList");
     protected final static String LIST_KEY_NAME = TestDataGenerator.randomFieldName("Key");
     protected final static ColumnType LIST_KEY_TYPE = ColumnType.Integer;
@@ -99,7 +107,7 @@ public List<String> getAssociatedModules()
     @Override
     protected String getProjectName()
     {
-        return "InlineImagesListTestProject";
+        return PROJECT_NAME;
     }
 
     @Override
@@ -111,7 +119,8 @@ protected BrowserType bestBrowser()
     @Override
     public void doCleanup(boolean afterTest) throws TestTimeoutException
     {
-        _containerHelper.deleteProject(getProjectName(), afterTest);
+        _containerHelper.deleteProject(PROJECT_NAME, afterTest);
+        _containerHelper.deleteProject(IMPORT_PROJECT_NAME, afterTest);
     }
 
     @Before
@@ -327,5 +336,51 @@ public final void testList() throws Exception
             assertTrue("Height of row 2 not in expected range (" + ROW_HEIGHT_SMALL_LBOUND + " to " + ROW_HEIGHT_SMALL_UBOUND + "). Actual height: " + sheet.getRow(2).getHeight(), (sheet.getRow(2).getHeight() > ROW_HEIGHT_SMALL_LBOUND) && (sheet.getRow(2).getHeight() < ROW_HEIGHT_SMALL_UBOUND));
             assertTrue("Height of row 3 not in expected range (" + ROW_HEIGHT_TEXT_LBOUND + " to " + ROW_HEIGHT_TEXT_UBOUND + "). Actual height: " + sheet.getRow(3).getHeight(), (sheet.getRow(3).getHeight() > ROW_HEIGHT_TEXT_LBOUND) && (sheet.getRow(3).getHeight() < ROW_HEIGHT_TEXT_UBOUND));
         }
+
+        log("Verify list archive export/import can round trip attachment successfully");
+        ManageListsGrid listsGrid = BeginPage.beginAt(this, getProjectName()).getGrid();
+        listsGrid.checkAllOnPage();
+        File listArchive = listsGrid.exportSelectedLists();
+
+        _containerHelper.createProject(IMPORT_PROJECT_NAME);
+
+        BeginPage.beginAt(this, IMPORT_PROJECT_NAME).importListArchive(listArchive);
+        _listHelper.goToList(LIST_NAME);
+
+        // Validate that list is imported as expected with attachments
+        assertElementPresent("Did not find the expected number of icons for images for " + LRG_PNG_FILE.getName(), Locator.xpath("//img[contains(@title, '" + LRG_PNG_FILE.getName() + "')]"), 1);
+        assertElementPresent("Did not find the expected number of icons for images for " + JPG01_FILE.getName(), Locator.xpath("//img[contains(@title, '" + JPG01_FILE.getName() + "')]"), 1);
+        assertElementPresent("Did not find the expected number of icons for images for " + PDF_FILE.getName(), Locator.xpath("//img[contains(@src, 'pdf.gif')]"), 1);
+        assertElementPresent("Did not find the expected text for " + PDF_FILE.getName(), Locator.xpath("//a[contains(text(), '" + PDF_FILE.getName() + "')]"), 1);
+
+        // Issue 53498: reject string attachment values for import
+        ImportDataPage listImportPage = _listHelper.clickImportData();
+        importFilePathError(listImportPage, "5", "absent.txt");
+        importFilePathError(listImportPage, "5", PDF_FILE.getName());
+        listImportPage.setCopyPasteMerge(false, true);
+        importFilePathError(listImportPage, "1", "absent.txt");
+        importFilePathError(listImportPage, "1", PDF_FILE.getName());
+        listImportPage.setCopyPasteMerge(true, true);
+        importFilePathError(listImportPage, "1", "absent.txt");
+        importFilePathError(listImportPage, "1", PDF_FILE.getName());
+        importFilePathError(listImportPage, "5", PDF_FILE.getName());
+    }
+
+    private void importFilePathError(ImportDataPage listImportPage, String key, String attachmentValue)
+    {
+        String pasteData = TestDataUtils.tsvStringFromRowMaps(List.of(Map.of(LIST_KEY_NAME, key, LIST_ATTACHMENT01_NAME, attachmentValue)),
+                List.of(LIST_KEY_NAME, LIST_ATTACHMENT01_NAME), true);
+        log(pasteData);
+        listImportPage.setText(pasteData);
+        listImportPage.submitExpectingError();
+        try
+        {
+            String expectedError = "Row 1: Can't upload '" + attachmentValue + "' to field " + LIST_ATTACHMENT01_NAME + " with type Attachment.";
+            checker().withScreenshot("import_error").verifyTrue("Invalid attachment error not as expected", isElementPresent(Locator.tagWithClass("div", "labkey-error").withText(expectedError)));
+        }
+        catch(NoSuchElementException nse)
+        {
+            checker().error("Invalid attachment error not present.");
+        }
     }
 }
diff --git a/src/org/labkey/test/tests/filecontent/FileContentUploadTest.java b/src/org/labkey/test/tests/filecontent/FileContentUploadTest.java
index e15f49c784..09c50d4fa3 100644
--- a/src/org/labkey/test/tests/filecontent/FileContentUploadTest.java
+++ b/src/org/labkey/test/tests/filecontent/FileContentUploadTest.java
@@ -353,8 +353,11 @@ public void testCalculateFileRootSize() throws Exception
     {
         String calculateFileRootSizeTask = "Calculate file root sizes";
         goToAdminConsole().clickSystemMaintenance().runMaintenanceTask(calculateFileRootSizeTask);
+
         Integer initialFileRootSize = getFileRootSize();
 
+        switchToMainWindow();
+
         goToProjectHome();
         File testFile = TestFileUtils.getSampleData("fileTypes/tsv_sample.tsv");
 
@@ -363,6 +366,9 @@ public void testCalculateFileRootSize() throws Exception
 
         goToAdminConsole().clickSystemMaintenance().runMaintenanceTask(calculateFileRootSizeTask);
         Integer finalFileRootSize = getFileRootSize();
+
+        switchToMainWindow();
+
         if (!checker().wrapAssertion(() -> Assertions.assertThat(finalFileRootSize)
                 .as("Crawled file root size").isGreaterThan(initialFileRootSize)))
         {