7-zip problem

[Sam_Zen]

I use the *.7z format as my favorite one for quite some time, but now I discovered, that it's not possible
to remove a file from the archive. Not from TC, not from using the 7-zip engine itself. What's wrong ?

[dott]

Solid 7z archives can't be modified, neither with 7-zip(Multiarc) nor with 7-zip plugin.

[Sam_Zen]

I didn't know that, thanks a lot. So nothing's wrong really.
Still a tiny drawback if one just want to replace some file in the archive by a newer version.

[dott]

Sorry, my previous answer, it's not quite true
It's possible to modify 7z archives in some ways:

• add new files; every new set of files(1 or more) are stored in a new solid block.
• remove or update files as long as this operation affect all the files in a solid block.

So if you plan to update the archive in the future, it would be a good idea for instance:
pack first all the files with extension *.xx1 then add *.xx2 files,.........., xxn files, this way you can delete or update each individual block.
Note: this method will increase the compression ratio.

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You may be interested in PowerArchiver, they (the PowerArchiver's guys ) claim that:

PowerArchiver 2007 introduces a new Transparent Update feature for 7-Zip archives, which allows you to quickly add or remove files even if the archive is "Solid."

It has a command line interface, so it would be possible to use it with multiarc.

I never test PowerArchiver though.