diff --git a/iiqtools/iiqtools_tar_to_zip.py b/iiqtools/iiqtools_tar_to_zip.py
index 9356238..2058091 100644
--- a/iiqtools/iiqtools_tar_to_zip.py
+++ b/iiqtools/iiqtools_tar_to_zip.py
@@ -10,7 +10,6 @@ the same, it's just a different compression format in InsightIQ 4.1.
 import os
 import re
 import zlib
-import struct
 import tarfile
 import zipfile
 import argparse
@@ -25,7 +24,7 @@ class BufferedZipFile(zipfile.ZipFile):
     stream the contents into a new zip file.
     """
 
-    def writebuffered(self, filename, file_handle):
+    def writebuffered(self, filename, file_handle, file_size):
         """Stream write data to the zip archive
 
         :param filename: **Required** The name to give the data once added to the zip file
@@ -33,35 +32,39 @@ class BufferedZipFile(zipfile.ZipFile):
 
         :param file_handle: **Required** The file-like object to read
         :type file_handle: Anything that supports the `read <https://docs.python.org/2/tutorial/inputoutput.html#methods-of-file-objects>`_ method
+
+        :param file_size: **Required** The size of the file in bytes
+        :type file_size: Integer
         """
         zinfo = zipfile.ZipInfo(filename=filename)
-
-        zinfo.file_size = file_size = 0
+        zinfo.file_size = file_size
         zinfo.flag_bits = 0x00
-        zinfo.header_offset = self.fp.tell()
+        zinfo.header_offset = self.fp.tell()    # Start of header bytes
 
         self._writecheck(zinfo)
         self._didModify = True
-
+        # Must overwrite CRC and sizes with correct data later
         zinfo.CRC = CRC = 0
         zinfo.compress_size = compress_size = 0
-        self.fp.write(zinfo.FileHeader())
+        # Compressed size can be larger than uncompressed size
+        zip64 = self._allowZip64 and \
+                zinfo.file_size * 1.05 > zipfile.ZIP64_LIMIT
+        self.fp.write(zinfo.FileHeader(zip64))
         if zinfo.compress_type == zipfile.ZIP_DEFLATED:
             cmpr = zlib.compressobj(zlib.Z_DEFAULT_COMPRESSION, zlib.DEFLATED, -15)
         else:
             cmpr = None
 
+        fsize = 0
         while True:
             buf = file_handle.read(1024 * 8)
             if not buf:
                 break
-
-            file_size = file_size + len(buf)
+            fsize = fsize + len(buf)
             CRC = binascii.crc32(buf, CRC) & 0xffffffff
             if cmpr:
                 buf = cmpr.compress(buf)
                 compress_size = compress_size + len(buf)
-
             self.fp.write(buf)
 
         if cmpr:
@@ -70,14 +73,19 @@ class BufferedZipFile(zipfile.ZipFile):
             self.fp.write(buf)
             zinfo.compress_size = compress_size
         else:
-            zinfo.compress_size = file_size
-
+            zinfo.compress_size = fsize
         zinfo.CRC = CRC
-        zinfo.file_size = file_size
-
-        position = self.fp.tell()
-        self.fp.seek(zinfo.header_offset + 14, 0)
-        self.fp.write(struct.pack("<LLL", zinfo.CRC, zinfo.compress_size, zinfo.file_size))
+        zinfo.file_size = fsize
+        if not zip64 and self._allowZip64:
+            if fsize > zipfile.ZIP64_LIMIT:
+                raise RuntimeError('File size has increased during compressing')
+            if compress_size > zipfile.ZIP64_LIMIT:
+                raise RuntimeError('Compressed size larger than uncompressed size')
+        # Seek backwards and write file header (which will now include
+        # correct CRC and file sizes)
+        position = self.fp.tell()       # Preserve current position in file
+        self.fp.seek(zinfo.header_offset, 0)
+        self.fp.write(zinfo.FileHeader(zip64))
         self.fp.seek(position, 0)
         self.filelist.append(zinfo)
         self.NameToInfo[zinfo.filename] = zinfo
@@ -189,7 +197,7 @@ def main(the_cli_args):
         log.info('Converting %s', the_file.name)
         try:
             filename = joinname(zip_export_dir, the_file.name)
-            zip_export.writebuffered(filename=filename, file_handle=file_handle)
+            zip_export.writebuffered(filename=filename, file_handle=file_handle, file_size=the_file.size)
         except (IOError, OSError) as doh:
             log.error(doh)
             log.error('Deleting zip file')
diff --git a/setup.py b/setup.py
index 504dd4b..2968bc9 100644
--- a/setup.py
+++ b/setup.py
@@ -9,7 +9,7 @@ setup(name="iiqtools",
       author="Nicholas Willhite,",
       author_email="willhite.nicholas@gmail.com",
       url='https://github.com/willnx/iiqtools',
-      version='2.1.1',
+      version='2.1.2',
       packages=find_packages(),
       include_package_data=True,
       scripts=['scripts/iiqtools_gather_info',

diff --git a/iiqtools_tests/test_iiqtools_tar_to_zip.py b/iiqtools_tests/test_iiqtools_tar_to_zip.py
index 797cadf..ec64b49 100644
--- a/iiqtools_tests/test_iiqtools_tar_to_zip.py
+++ b/iiqtools_tests/test_iiqtools_tar_to_zip.py
@@ -26,11 +26,10 @@ class TestBufferedZipFile(unittest.TestCase):
         """Runs after every tests case"""
         os.remove(self.filepath)
 
-    @patch.object(iiqtools_tar_to_zip, 'struct')
     @patch.object(iiqtools_tar_to_zip, 'binascii')
-    def test_basic(self, fake_binascii, fake_struct):
+    def test_basic(self, fake_binascii):
         """BufferedZipFile - writebuffered is callable"""
-        self.zipfile.writebuffered(filename='foo', file_handle=self.fake_file)
+        self.zipfile.writebuffered(filename='foo', file_handle=self.fake_file, file_size=9000)
 
 
 class TestCheckTar(unittest.TestCase):

struct error export too large.
I am getting errors trying to convert to a zip.  Looks like the export was too large.
```
[administrator@vcmcinsightiq tmp]$ /opt/rh/python27/root/usr/bin/iiqtools_tar_to_zip -s insightiq_export_1522783418.tar.gz -o /mnt/10.193.6.113/ifs/data/IIQ2/
2018-04-04 20:13:37,625 - INFO - Converting insightiq_export_1522783418.tar.gz to zip format
2018-04-04 20:34:32,536 - INFO - InsightIQ datastore tar export contained 2 files
2018-04-04 20:34:32,536 - INFO - Converting insightiq_export_1522783418/vcmc-12kisilon_00151b00007a2716ce4a1504000067458b6b_config.json
2018-04-04 20:34:32,560 - INFO - Converting insightiq_export_1522783418/vcmc-12kisilon_00151b00007a2716ce4a1504000067458b6b.dump
Traceback (most recent call last):
  File "/opt/rh/python27/root/usr/bin/iiqtools_tar_to_zip", line 11, in <module>
    sys.exit(main(sys.argv[1:]))
  File "/opt/rh/python27/root/usr/lib/python2.7/site-packages/iiqtools/iiqtools_tar_to_zip.py", line 192, in main
    zip_export.writebuffered(filename=filename, file_handle=file_handle)
  File "/opt/rh/python27/root/usr/lib/python2.7/site-packages/iiqtools/iiqtools_tar_to_zip.py", line 80, in writebuffered
    self.fp.write(struct.pack("<LLL", zinfo.CRC, zinfo.compress_size, zinfo.file_size))
struct.error: 'L' format requires 0 <= number <= 4294967295
```
iiqtools_tests/test_iiqtools_tar_to_zip.py::TestBufferedZipFile::test_basic
iiqtools_tests/test_iiqtools_tar_to_zip.py::TestGetTimestampFromExport::test_absolute_path iiqtools_tests/test_iiqtools_tar_to_zip.py::TestParseCli::test_no_args iiqtools_tests/test_iiqtools_tar_to_zip.py::TestParseCli::test_returns_namespace iiqtools_tests/test_iiqtools_tar_to_zip.py::TestParseCli::test_missing_required iiqtools_tests/test_iiqtools_tar_to_zip.py::TestJoinname::test_absolute_path iiqtools_tests/test_iiqtools_tar_to_zip.py::TestJoinname::test_relative_path iiqtools_tests/test_iiqtools_tar_to_zip.py::TestCheckTar::test_not_a_file iiqtools_tests/test_iiqtools_tar_to_zip.py::TestCheckTar::test_bad_file_name iiqtools_tests/test_iiqtools_tar_to_zip.py::TestCheckTar::test_valid_tar iiqtools_tests/test_iiqtools_tar_to_zip.py::TestCheckTar::test_not_a_tar