Sometime to reduce the download size, file uploaders will pack files into a compressed archive and then re-compress the archive file into another archive. Often, the uploader will do this a number of times. The objective is achieved, but it drives the downloader crazy from repeated extractions that is required to get the original files. Then afterwards they have to clean up the mess.
Multi Unpacker is an excellent open source program that solves this problem. This free tool can recursively extract multiple RAR or ZIP archives, and also clean up all the extracted archive files. Multi Unpacker requires WinRAR to be installed on your computer, because it uses WinRAR to perform the actual extraction.
When the archive is nested, that is, one archive packed into another which is packed into another, choose the option ‘Extract nested archive’. If disk space is low, and the extracted files are large in size, you can choose to delete the archive files so that you are left with the contents of only the last archive. All intermediate archive files are deleted, including – pay attention, the original archive file. If you don’t want to lose the original downloaded archive file DO NOT check this option.
Also, I recommend to keep ‘Overwrite existing files’ option uncheck so as not to inadvertently overwrite compressed archives that were named similarly in each nested archive.
The only thing I didn’t like about this program is that you cannot perform an operation on the desired archive file directly. Multi Unpacker will only accept folders as inputs and will scan the contents for archives, and then extract all archives it finds. The workaround to this issue is to create a new folder, move the archive you want to extract into it and point the program to that folder.
Related: ExtractNow unzips multiple archives at once
I cannot believe that uploaders re-compress there files over and over again, for the reason you state. I think it's because file sniffers, especially in online storage services, don't scan so deep. Even some anti-virus software sometimes fails to deep scan such files in the past properly.
You maybe right. That's one way to escape file sniffers.
BTW, matroska unpacker looks terrific. Thanks.