TL;DR: Use `ditto` instead of `unzip` for large zip archives.
Today I downloaded the Microsoft Edge on Win10 VM from Microsoft. It downloads as either a single 5.42 GB `.zip` file, or as size separate smaller `.zip` file segments that you can then join together. I initially downloaded the smaller segments, verified their MD5 hashes, and tried to unzip the combined file by double-clicking on it. But, this just resulted in a `.cpgz` file! So, after some web searching, I decided to try `unzip` from the command line. This failed as well, but at least gave me an error message:
$ unzip Microsoft\ Edge.Win10.For.Mac.VirtualBox.zip Archive: Microsoft Edge.Win10.For.Mac.VirtualBox.zip warning [Microsoft Edge.Win10.For.Mac.VirtualBox.zip]: 1121740098 extra bytes at beginning or within zipfile (attempting to process anyway) error [Microsoft Edge.Win10.For.Mac.VirtualBox.zip]: start of central directory not found; zipfile corrupt. (please check that you have transferred or created the zipfile in the appropriate BINARY mode and that you have compiled UnZip properly)
I even tried downloading the single 5.42 GB `.zip` file, thinking that perhaps something was going wrong when I combined the smaller segments. No dice.
I started thinking that perhaps the `.zip` file was too large for `unzip`, so I searched some more and found a post on Stack Overflow suggesting to try the `ditto` command line tool. Bingo! Now I was in business:
$ ditto -x -k Microsoft\ Edge.Win10.For.Mac.VirtualBox.zip edge
I was able to successfully unzip the file and import the VM into VirtualBox.