diff --git a/src/read.rs b/src/read.rs
index 91080941..a6763030 100644
--- a/src/read.rs
+++ b/src/read.rs
@@ -242,7 +242,7 @@ pub(crate) fn find_content<'a>(
 pub(crate) fn make_crypto_reader<'a>(
     compression_method: CompressionMethod,
     crc32: u32,
-    last_modified_time: DateTime,
+    mut last_modified_time: Option<DateTime>,
     using_data_descriptor: bool,
     reader: io::Take<&'a mut dyn Read>,
     password: Option<&[u8]>,
@@ -269,7 +269,10 @@ pub(crate) fn make_crypto_reader<'a>(
             vendor_version,
         },
         (Some(password), None) => {
-            let validator = if using_data_descriptor {
+            if !using_data_descriptor {
+                last_modified_time = None;
+            }
+            let validator = if let Some(last_modified_time) = last_modified_time {
                 ZipCryptoValidator::InfoZipMsdosTime(last_modified_time.timepart())
             } else {
                 ZipCryptoValidator::PkzipCrc32(crc32)
@@ -1009,8 +1012,7 @@ fn central_header_to_zip_file_inner<R: Read>(
             CompressionMethod::from_u16(compression_method)
         },
         compression_level: None,
-        last_modified_time: DateTime::try_from_msdos(last_mod_date, last_mod_time)
-            .unwrap_or_else(|_| DateTime::default()),
+        last_modified_time: DateTime::try_from_msdos(last_mod_date, last_mod_time).ok(),
         crc32,
         compressed_size: compressed_size as u64,
         uncompressed_size: uncompressed_size as u64,
@@ -1252,7 +1254,7 @@ impl<'a> ZipFile<'a> {
     }
 
     /// Get the time the file was last modified
-    pub fn last_modified(&self) -> DateTime {
+    pub fn last_modified(&self) -> Option<DateTime> {
         self.data.last_modified_time
     }
     /// Returns whether the file is actually a directory
@@ -1397,8 +1399,7 @@ pub fn read_zipfile_from_stream<'a, R: Read>(reader: &'a mut R) -> ZipResult<Opt
         using_data_descriptor: false,
         compression_method,
         compression_level: None,
-        last_modified_time: DateTime::try_from_msdos(last_mod_date, last_mod_time)
-            .unwrap_or_else(|_| DateTime::default()),
+        last_modified_time: DateTime::try_from_msdos(last_mod_date, last_mod_time).ok(),
         crc32,
         compressed_size: compressed_size as u64,
         uncompressed_size: uncompressed_size as u64,
@@ -1525,7 +1526,7 @@ mod test {
         let mut file1 = reader1.by_index(0).unwrap();
         let mut file2 = reader2.by_index(0).unwrap();
 
-        let t = file1.last_modified();
+        let t = file1.last_modified().unwrap();
         assert_eq!(
             (
                 t.year(),
diff --git a/src/types.rs b/src/types.rs
index 5645e922..217088fd 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -380,7 +380,7 @@ pub struct ZipFileData {
     /// Compression level to store the file
     pub compression_level: Option<i64>,
     /// Last modified time. This will only have a 2 second precision.
-    pub last_modified_time: DateTime,
+    pub last_modified_time: Option<DateTime>,
     /// CRC32 checksum
     pub crc32: u32,
     /// Size of the file in the ZIP
@@ -615,7 +615,7 @@ mod test {
             using_data_descriptor: false,
             compression_method: crate::compression::CompressionMethod::Stored,
             compression_level: None,
-            last_modified_time: DateTime::default(),
+            last_modified_time: None,
             crc32: 0,
             compressed_size: 0,
             uncompressed_size: 0,
diff --git a/src/write.rs b/src/write.rs
index 3f104204..d2f2883f 100644
--- a/src/write.rs
+++ b/src/write.rs
@@ -573,7 +573,7 @@ impl<A: Read + Write + Seek> ZipWriter<A> {
             let mut options = FileOptions::<ExtendedFileOptions> {
                 compression_method: src_data.compression_method,
                 compression_level: src_data.compression_level,
-                last_modified_time: src_data.last_modified_time,
+                last_modified_time: src_data.last_modified_time.unwrap_or_else(DateTime::default_for_write),
                 permissions: src_data.unix_mode(),
                 large_file: src_data.large_file,
                 encrypt_with: None,
@@ -594,7 +594,7 @@ impl<A: Read + Write + Seek> ZipWriter<A> {
             let mut options = FileOptions::<()> {
                 compression_method: src_data.compression_method,
                 compression_level: src_data.compression_level,
-                last_modified_time: src_data.last_modified_time,
+                last_modified_time: src_data.last_modified_time.unwrap_or_else(DateTime::default_for_write),
                 permissions: src_data.unix_mode(),
                 large_file: src_data.large_file,
                 encrypt_with: None,
@@ -782,6 +782,7 @@ impl<W: Write + Seek> ZipWriter<W> {
                 ),
                 _ => (options.compression_method, None),
             };
+            let last_modified_time = options.last_modified_time;
             let file = ZipFileData {
                 system: System::Unix,
                 version_made_by: DEFAULT_VERSION,
@@ -789,7 +790,7 @@ impl<W: Write + Seek> ZipWriter<W> {
                 using_data_descriptor: false,
                 compression_method,
                 compression_level: options.compression_level,
-                last_modified_time: options.last_modified_time,
+                last_modified_time: Some(options.last_modified_time),
                 crc32: raw_values.crc32,
                 compressed_size: raw_values.compressed_size,
                 uncompressed_size: raw_values.uncompressed_size,
@@ -826,8 +827,8 @@ impl<W: Write + Seek> ZipWriter<W> {
             #[allow(deprecated)]
             writer.write_u16_le(file.compression_method.to_u16())?;
             // last mod file time and last mod file date
-            writer.write_u16_le(file.last_modified_time.timepart())?;
-            writer.write_u16_le(file.last_modified_time.datepart())?;
+            writer.write_u16_le(last_modified_time.timepart())?;
+            writer.write_u16_le(last_modified_time.datepart())?;
             // crc-32
             writer.write_u32_le(file.crc32)?;
             // compressed size and uncompressed size
@@ -1193,7 +1194,7 @@ impl<W: Write + Seek> ZipWriter<W> {
     {
         let mut options = SimpleFileOptions::default()
             .large_file(file.compressed_size().max(file.size()) > spec::ZIP64_BYTES_THR)
-            .last_modified_time(file.last_modified())
+            .last_modified_time(file.last_modified().unwrap_or_else(DateTime::default_for_write))
             .compression_method(file.compression());
         if let Some(perms) = file.unix_mode() {
             options = options.unix_permissions(perms);
@@ -1813,9 +1814,10 @@ fn write_central_directory_header<T: Write>(writer: &mut T, file: &ZipFileData)
     // compression method
     #[allow(deprecated)]
     writer.write_u16_le(file.compression_method.to_u16())?;
+    let last_modified_time = file.last_modified_time.unwrap_or_else(DateTime::default_for_write);
     // last mod file time + date
-    writer.write_u16_le(file.last_modified_time.timepart())?;
-    writer.write_u16_le(file.last_modified_time.datepart())?;
+    writer.write_u16_le(last_modified_time.timepart())?;
+    writer.write_u16_le(last_modified_time.datepart())?;
     // crc-32
     writer.write_u32_le(file.crc32)?;
     // compressed size