Recently I’ve been having some issues where I 7z a dmg on windows before putting it in my backup drive, but I also send it to my MacBook to update/install, then the file inside can’t be opened because it says the disc image is corrupted? But if I use Keka on Mac it should work, is there something that gets broken going from windows to an exFAT disk to Mac? And what can I do to still be able to use 7zip and the archived dmgs will open and install successfully? Want to keep using windows since my laptop is better at compressing since it’s newer and saves time, and hopefully I can be able to use every compressed dmg in the future… is it maybe related to 7zip itself? Or is it from the hard drive that breaks it?

 

It's the same when putting the dmg into a folder, and 7zip that?
Other: I don't know if 7zip can do a Store mode, with no compression? That would be preferable.
Below there's something about file system limitations on Unix based systems, which MacOS is. Read under 'Limitations':
https://en.wikipedia.org/wiki/7z

 

It doesn't sound like it.

I never have any problems opening things that have been archived using 7zip. Create a "problem 7 zip" using some files, like a .wav file or something (of a decent size, few mbs) you do not mind uploading. When your Mac can't unzip it, upload it on workupload or other file transfer site.

If it can be opened on another Mac; it is your Mac with the problem, somehow. If it can't, then the problem is somewhere on your Windows machine/7zip.

 

Would it be possible to just compress to tar.xz instead? Otherwise I’ll just have to leave dmg uncompressed but I make sure to save space by compressing whatever I can before backing up, so would unzipping the 7z on windows and transferring the dmg from there work maybe?

 

It’s less of a”Mac can’t unzip it” and more of it just can’t read the dmg inside

 

I never make .7z files, but my guess then would be due to either too high compression setting in 7zip, possible problem with the media/drive and the file is corrupting because of it, or something like that.

Have you tried mounting the dmg (disk image) and then dragging the installer/files inside the dmg and copying them over to the local drive or desktop, then running?

If you can mount the dmg file, you could probably find the installer is a pkg file inside that disk image. Also, you should compare the size of files resulting from using 7zip and another archiver on Windows. You are probably not going to save much space by compressing a dmg file.