diff --git a/Tasks/ArchiveFilesV2/Tests/L0.ts b/Tasks/ArchiveFilesV2/Tests/L0.ts
index cfadf26f0c67..b7ce25911f1a 100644
--- a/Tasks/ArchiveFilesV2/Tests/L0.ts
+++ b/Tasks/ArchiveFilesV2/Tests/L0.ts
@@ -190,5 +190,32 @@ describe('ArchiveFiles L0 Suite', function () {
             assert(tr.stdout.indexOf('Creating archive') > -1, 'Should have tried to create archive');
             assert(fs.existsSync(expectedArchivePath), `Should have successfully created the archive at ${expectedArchivePath}, instead directory contents are ${fs.readdirSync(path.dirname(expectedArchivePath))}`);
         });
+
+        it('Successfully adds a single file to an existing archive', async function () {
+            this.timeout(5000);
+            process.env['archiveType'] = 'zip';
+            process.env['archiveFile'] = 'singleFileArchive.zip';
+            process.env['includeRootFolder'] = 'false';
+            process.env['replaceExistingArchive'] = 'false';
+            expectedArchivePath = path.join(__dirname, 'test_output', 'singleFileArchive.zip');
+
+            // Create the initial archive
+            let tp1: string = path.join(__dirname, 'L0CreateArchive.js');
+            let tr1: ttm.MockTestRunner = new ttm.MockTestRunner(tp1);
+            await tr1.runAsync();
+            assert(fs.existsSync(expectedArchivePath), 'Should have created the initial archive');
+
+            // Add a single file to the existing archive
+            let tp2: string = path.join(__dirname, 'L0AddSingleFileToExisting.js');
+            let tr2: ttm.MockTestRunner = new ttm.MockTestRunner(tp2);
+            await tr2.runAsync();
+
+            assert(tr2.succeeded, 'Task should have succeeded');
+            assert(tr2.stdout.indexOf('Adding to existing archive') > -1 || 
+                  tr2.stdout.indexOf('Adding file to archive') > -1 ||
+                  tr2.stdout.indexOf('Archiving file:') > -1, 
+                  'Should have added file to archive');
+            assert(fs.existsSync(expectedArchivePath), 'Archive should still exist');
+        });
     }
 });
diff --git a/Tasks/ArchiveFilesV2/Tests/L0AddSingleFileToExisting.ts b/Tasks/ArchiveFilesV2/Tests/L0AddSingleFileToExisting.ts
new file mode 100644
index 000000000000..baf308ec5b53
--- /dev/null
+++ b/Tasks/ArchiveFilesV2/Tests/L0AddSingleFileToExisting.ts
@@ -0,0 +1,17 @@
+import tmrm = require('azure-pipelines-task-lib/mock-run');
+import path = require('path');
+
+let taskPath = path.join(__dirname, '..', 'archivefiles.js');
+let tmr: tmrm.TaskMockRunner = new tmrm.TaskMockRunner(taskPath);
+
+process.env['AGENT_TEMPDIRECTORY'] = path.join(__dirname, 'test_temp');
+
+// First, set up to create an initial archive
+tmr.setInput('rootFolderOrFile', path.join(__dirname, 'test_folder', 'a', 'abc.txt'));
+tmr.setInput('includeRootFolder', process.env['includeRootFolder']);
+tmr.setInput('archiveType', process.env['archiveType']);
+tmr.setInput('archiveFile', path.join(__dirname, 'test_output', process.env['archiveFile']));
+tmr.setInput('replaceExistingArchive', process.env['replaceExistingArchive'] || 'false');
+tmr.setInput('tarCompression', 'gz');
+
+tmr.run(true);
\ No newline at end of file
diff --git a/Tasks/ArchiveFilesV2/archivefiles.ts b/Tasks/ArchiveFilesV2/archivefiles.ts
index 80002e17f8fd..6d10989fab53 100644
--- a/Tasks/ArchiveFilesV2/archivefiles.ts
+++ b/Tasks/ArchiveFilesV2/archivefiles.ts
@@ -45,12 +45,19 @@ function findFiles(): string[] {
         }
         return [path.basename(rootFolderOrFile)];
     } else {
-        var fullPaths: string[] = tl.ls('-A', [rootFolderOrFile]);
-        var baseNames: string[] = [];
-        for (var i = 0; i < fullPaths.length; i++) {
-            baseNames[i] = path.basename(fullPaths[i]);
+        // Check if rootFolderOrFile is a file (only when feature flag is enabled)
+        if (tl.getPipelineFeature("DistributedTasks.Task.ArchiveOneFileWithRootFolderInput") && 
+            fs.existsSync(rootFolderOrFile) && 
+            fs.statSync(rootFolderOrFile).isFile()) {
+            return [path.basename(rootFolderOrFile)];
+        } else {
+            var fullPaths: string[] = tl.ls('-A', [rootFolderOrFile]);
+            var baseNames: string[] = [];
+            for (var i = 0; i < fullPaths.length; i++) {
+                baseNames[i] = path.basename(fullPaths[i]);
+            }
+            return baseNames;
         }
-        return baseNames;
     }
 }