diff --git a/Example/ObjectiveCExampleTests/SSZipArchiveTests.m b/Example/ObjectiveCExampleTests/SSZipArchiveTests.m
index 1fe9316..e027f92 100644
--- a/Example/ObjectiveCExampleTests/SSZipArchiveTests.m
+++ b/Example/ObjectiveCExampleTests/SSZipArchiveTests.m
@@ -467,6 +467,17 @@ int twentyMB = 20 * 1024 * 1024;
     XCTAssert(fileSize < fileSize2, @"keepParentDirectory should produce a strictly bigger archive.");
 }
 
+/// <https://github.com/ZipArchive/ZipArchive/issues/621>
+- (void)testZippingNonDirectoryWithContentsOfDirectory {
+    NSString *inputPath = [[NSBundle bundleForClass:[self class]] pathForResource:@"TestArchive" ofType:@"zip"];
+    NSString *outputPath = [self _cachesPath:@"ZippingNonDirectory"];
+    NSString *zipPath = [outputPath stringByAppendingPathComponent:@"ZippingNonDirectory.zip"];
+
+    BOOL success = [SSZipArchive createZipFileAtPath:zipPath withContentsOfDirectory:inputPath];
+    XCTAssertTrue(!success, @"create zip success");
+}
+
+/// Using `keepParentDirectory:YES`
 - (void)testZippingAndUnzippingEmptyDirectoryWithPassword {
     
     NSString *inputPath = [self _cachesPath:@"Empty"];
@@ -477,12 +488,43 @@ int twentyMB = 20 * 1024 * 1024;
     BOOL success = [SSZipArchive createZipFileAtPath:zipPath withContentsOfDirectory:inputPath keepParentDirectory:YES withPassword:@"password"];
     XCTAssertTrue(success, @"create zip failure");
     
-    outputPath = [self _cachesPath:@"EmptyDirectory"];
+    outputPath = [self _cachesPath:@"EmptyOutput"];
     
     // unzipping a directory doesn't require a password
     id<SSZipArchiveDelegate> delegate = [ProgressDelegate new];
     success = [SSZipArchive unzipFileAtPath:zipPath toDestination:outputPath overwrite:YES password:nil error:nil delegate:delegate];
     XCTAssertTrue(success, @"unzip failure");
+
+    NSString *emptyPath = [outputPath stringByAppendingPathComponent:@"Empty"];
+    BOOL isDirectory;
+    XCTAssertTrue([[NSFileManager defaultManager] fileExistsAtPath:emptyPath isDirectory:&isDirectory], @"Empty unzipped");
+    XCTAssertTrue(isDirectory, @"Empty is a directory");
+}
+
+/// Using `withFilesAtPaths:`
+- (void)testZippingAndUnzippingEmptyDirectoryWithFilesAtPaths {
+
+    NSString *inputPath = [self _cachesPath:@"EmptyWithSubdirectory"];
+    NSString *emptySubdirectory = [inputPath stringByAppendingPathComponent:@"Empty"];
+    BOOL success = [[NSFileManager defaultManager] createDirectoryAtPath:emptySubdirectory withIntermediateDirectories:YES attributes:nil error:NULL];
+    XCTAssertTrue(success, @"create folder failure");
+
+    // zipping files
+    NSString *outputPath = [self _cachesPath:@"Zipped"];
+    NSString *zipPath = [outputPath stringByAppendingPathComponent:@"EmptyWithSubdirectory.zip"];
+    success = [SSZipArchive createZipFileAtPath:zipPath withFilesAtPaths:@[emptySubdirectory]];
+    XCTAssertTrue(success, @"create zip failure");
+
+    // unzipping files
+    outputPath = [self _cachesPath:@"EmptyWithSubdirectoryOutput"];
+    id<SSZipArchiveDelegate> delegate = [ProgressDelegate new];
+    success = [SSZipArchive unzipFileAtPath:zipPath toDestination:outputPath overwrite:YES password:nil error:nil delegate:delegate];
+    XCTAssertTrue(success, @"unzip failure");
+
+    NSString *emptyPath = [outputPath stringByAppendingPathComponent:@"Empty"];
+    BOOL isDirectory;
+    XCTAssertTrue([[NSFileManager defaultManager] fileExistsAtPath:emptyPath isDirectory:&isDirectory], @"Empty unzipped");
+    XCTAssertTrue(isDirectory, @"Empty is a directory");
 }
 
 - (void)testUnzippingEmptyArchive {
@@ -592,14 +634,14 @@ int twentyMB = 20 * 1024 * 1024;
 // `LargeArchive.zip` to the project and uncomment out these lines to test.
 //
 //- (void)testUnzippingLargeFiles {
-//	NSString *zipPath = [[NSBundle bundleForClass:[self class]] pathForResource:@"LargeArchive" ofType:@"zip"];
-//	NSString *outputPath = [self _cachesPath:@"Large"];
+//    NSString *zipPath = [[NSBundle bundleForClass:[self class]] pathForResource:@"LargeArchive" ofType:@"zip"];
+//    NSString *outputPath = [self _cachesPath:@"Large"];
 //
-//  BOOL success = [SSZipArchive unzipFileAtPath:zipPath toDestination:outputPath];
-//  XCTAssertTrue(success, @"unzip failure");
+//    BOOL success = [SSZipArchive unzipFileAtPath:zipPath toDestination:outputPath];
+//    XCTAssertTrue(success, @"unzip failure");
 //}
 
--(void)testShouldProvidePathOfUnzippedFileInDelegateCallback {
+- (void)testShouldProvidePathOfUnzippedFileInDelegateCallback {
     CollectingDelegate *collector = [CollectingDelegate new];
     NSString *zipPath = [[NSBundle bundleForClass:[self class]] pathForResource:@"TestArchive" ofType:@"zip"];
     NSString *outputPath = [self _cachesPath:@"Regular"];
@@ -692,7 +734,6 @@ int twentyMB = 20 * 1024 * 1024;
     XCTAssertTrue(iterations == noFiles, "All files should be present in the exported directory");
 }
 
-//PR #560
 - (void)testSymlinkZippingWithFilesAtPaths {
     NSString *outputDir = [self _cachesPath:@"ZippingSymlinkWithFilesAtPaths"];
 
@@ -738,7 +779,6 @@ int twentyMB = 20 * 1024 * 1024;
     XCTAssertEqualObjects(realFilePath, realFilePathUnzip);
 }
 
-//PR #560
 - (void)testSymlinkZippingWithContentsOfDirectory {
     NSString *outputDir = [self _cachesPath:@"ZippingSymlinkWithContentsOfDirectory"];
 
@@ -811,7 +851,8 @@ int twentyMB = 20 * 1024 * 1024;
         path = [path stringByAppendingPathComponent:directory];
     }
 
-    [[NSFileManager defaultManager] createDirectoryAtPath:path withIntermediateDirectories:YES attributes:nil error:nil];
+    BOOL success = [[NSFileManager defaultManager] createDirectoryAtPath:path withIntermediateDirectories:YES attributes:nil error:nil];
+    XCTAssertTrue(success, @"%@", path);
 
     return path;
 }
diff --git a/SSZipArchive/SSZipArchive.h b/SSZipArchive/SSZipArchive.h
index 7787464..30f1819 100644
--- a/SSZipArchive/SSZipArchive.h
+++ b/SSZipArchive/SSZipArchive.h
@@ -147,7 +147,7 @@ typedef NS_ENUM(NSInteger, SSZipArchiveErrorCode) {
 - (BOOL)writeFile:(NSString *)path withPassword:(nullable NSString *)password;
 - (BOOL)writeFileAtPath:(NSString *)path withFileName:(nullable NSString *)fileName withPassword:(nullable NSString *)password;
 - (BOOL)writeFileAtPath:(NSString *)path withFileName:(nullable NSString *)fileName compressionLevel:(int)compressionLevel password:(nullable NSString *)password AES:(BOOL)aes;
-///write symlink files
+/// write symlink files
 - (BOOL)writeSymlinkFileAtPath:(NSString *)path withFileName:(nullable NSString *)fileName compressionLevel:(int)compressionLevel password:(nullable NSString *)password AES:(BOOL)aes;
 /// write data
 - (BOOL)writeData:(NSData *)data filename:(nullable NSString *)filename withPassword:(nullable NSString *)password;
diff --git a/SSZipArchive/SSZipArchive.m b/SSZipArchive/SSZipArchive.m
index aef89e8..96acc03 100644
--- a/SSZipArchive/SSZipArchive.m
+++ b/SSZipArchive/SSZipArchive.m
@@ -811,8 +811,19 @@ BOOL _fileIsSymbolicLink(const unz_file_info *fileInfo);
     BOOL success = [zipArchive open];
     if (success) {
         NSUInteger total = paths.count, complete = 0;
+        // use a local fileManager (queue/thread compatibility)
+        NSFileManager *fileManager = [[NSFileManager alloc] init];
         for (NSString *filePath in paths) {
-            success &= [zipArchive writeFile:filePath withPassword:password];
+            BOOL isDir;
+            [fileManager fileExistsAtPath:filePath isDirectory:&isDir];
+            if (!isDir) {
+                // file
+                success &= [zipArchive writeFile:filePath withPassword:password];
+            } else {
+                // directory
+                // we ignore its content, to allow for archiving this path only
+                success &= [zipArchive writeFolderAtPath:filePath withFolderName:filePath.lastPathComponent withPassword:password];
+            }
             if (progressHandler) {
                 complete++;
                 progressHandler(complete, total);
@@ -861,9 +872,16 @@ BOOL _fileIsSymbolicLink(const unz_file_info *fileInfo);
         NSDirectoryEnumerator *dirEnumerator = [fileManager enumeratorAtPath:directoryPath];
         NSArray<NSString *> *allObjects = dirEnumerator.allObjects;
         NSUInteger total = allObjects.count, complete = 0;
-        if (keepParentDirectory && !total) {
-            allObjects = @[@""];
-            total = 1;
+        if (!total) {
+            // <https://github.com/ZipArchive/ZipArchive/issues/621> let's check if it's an actual directory.
+            BOOL isDir;
+            [fileManager fileExistsAtPath:directoryPath isDirectory:&isDir];
+            if (!isDir) {
+                success = NO;
+            } else if (keepParentDirectory) {
+                allObjects = @[@""];
+                total = 1;
+            }
         }
         for (__strong NSString *fileName in allObjects) {
             NSString *fullFilePath = [directoryPath stringByAppendingPathComponent:fileName];