C-Command Software Forum

Should I use DMGs for archiving macOS Installers?

I am trying to make my own archive of macOS installers. As you know, Apple has done a terrible job of making these available (you download a .dmg which contains a .pkg which installs the .app but the .app gets assembled by some script in the .pkg so you can’t just extract the .app…YUCK).

Once I have these installer apps, I want to create a way that I can store them securely. I have been using .tar archives (I haven’t bothered compressing them because I figure the space savings would be minor).

I could use .zip of course, but it occurred to me that maybe .dmg is the way to go. I could make them read-only so there’s no worries about something changing on them once I know that they are working, and DMGs sync fine via Dropbox, etc. so it seems like a good option.

Am I missing anything? Any reason to use DMG or not use DMG for this? (These would obviously just be for me, and don’t need to be fancy, just reliable so I know that I can use them later)

Seems fine to me. I have done that with installers, too. A read-only .dmg will have a checksum to help detect damage, and unlike .tar/.zip you wouldn’t need to extract the contents to disk to access it.

I think this is possible, but now that I’m thinking about it, I should probably ask you who would know.

Say I make USB installers for Lion to Catalina, using something like Disk Maker X.

Can I then make DMG images of those USB installers, which I could use to make other bootable USB installers in the future? My thought is that the USB installer could get lost or whatnot, so having the DMGs would be a good thing to have as a backup.

Again, the answer to me seems like it would have to be 'yes" but assumptions have a way of biting me in the *ss.

Yes, if you drag the bootable volume onto DropDMG, it will make a device image.

DropDMG can make installer disks, too.

Have you gotten the softwareupdate --fetch-full-installer --full-installer-version 10.14.6 thing to work? It has never once worked for me. I had to download them all via the App Store in a VM.

I only had intermittent success with that.