Problems when Unpacking Zip files

If you encounter an error message like "The Compressed (zipped) Folder ... is Invalid" when unpacking a zip file downloaded from Safelink, you may have encountered a limitation in the built-in unpacking tool included with Windows.

The built-in zip unpacking tool in Windows has two known limitations that affect the ability to unpack zip files exported from Safelink.

The first is that, even in recent versions of Windows, the built-in unpacking tool is unable to unpack zip files containing long folder and file names.  Many Windows APIs, including the ones used by Explorer and the built-in file unzip tool, have a maximum total path length of 260 characters (see ). The limit applies to the total length of the filename plus the lengths of the folder names that the file lives within.

The second is that older versions of Windows do not include support for Zip64 formatted files, and can only unpack the older Zip32 format.  Safelink produces Zip32 files where possible, and automatically switches to using the Zip64 format when necessary.  Zip32 files can contain at most 4GB of data, and at most 65.536 documents.  If you create an export that exceeds either of these limits, you will receive a valid Zip64 formatted file. 
We would suggest that you use an alternative unpacking tool, such as the freely available 7-Zip, which can handle the Zip64 format, as well as folder and file paths of any length.