MASV Rush automatically creates a downloadable ZIP archive for you to download several files with one click.

Most (but not all) utilities are able to expand ZIP archives that contain files larger than 4GB. It really depends on whether they implement the “standard” ZIP64 format used to archive large files.

Specifically, macOS Finder, macOS Archive Utility and Safari download-auto-expansion do NOT support the ZIP64 format used to encode large files (they use a different, non-standard format). Symptoms of this problem include:

  • the “Unable to expand ZIP file, Error 2” message, or
  • Safari’s “Decompression failed” message in the Show Downloads window.

The result is that a ZIP file containing a large file (4GB+), created by macOS Finder (right-click, compress) or the macOS Archive Utility, will not be readable on Windows or Linux systems.  Also, a ZIP64 archive created by MASV Rush containing a large file (4GB+) will not be readable using macOS Finder, macOS Archive Utility, or Safari download-auto-expansion (the package download completes and the package is stored in the download folder, but is not auto-expand by Safari).

We realize this is not an ideal situation, but we are somewhat handcuffed by a questionable implementation of the ZIP format for large files by these otherwise trusted macOS tools - and we're currently working on a macOS-friendly ZIP file format that would be made available to macOS users.

Workarounds for macOS

When receiving a ZIP file from MASV Rush, we recommend using the StuffIt Expander 16 or the command-line utility “unzip” (described below), or any other ZIP utility application that supports the ZIP64 format, when working with an archive containing individual files larger than 4GB.

When sending multiple files, you may want to have MASV Rush create (by default) a ZIP64 package for you by selecting the individual files or folders via the Rush uploader. Alternatively, the command-line utility “zip” can be used to generate a ZIP64-compatible archive that can subsequently be transferred to recipients using Rush.

macOS command-line “unzip” work-around:

  1. Open “Terminal”
  2. Check that the "unzip" command is installed and reports a version of 6.0 or better:
$ unzip -v
UnZip 6.00 [...]

  3. Navigate to your download directory, e.g.:
$ cd ~/Downloads/

 4. Expand the ZIP file using “unzip”, e.g.:
$ unzip -d destination_folder

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