Error while trying to make a password protected .DMG

[stanw]

I'm trying to make a password protected .DMG on an external drive. It gets to the point where it starts the process though it finishes with a message that it failed, along with an error. I tried 3 times. Any ideas?

 

[treekram]

Check the permissions on the drive/directory. The following is an article with possible solutions.
https://www.cnet.com/news/solving-read-only-conditions-for-external-hard-drives/

Also do you have enough space on the drive for the .dmg? Also, if the drive is formatted for FAT32, the maximum file size is 4GB. (If you're actually using High Sierra, there's a bug where this limit is even less.)

If that doesn't resolve the issue, if you have space on an internal drive, you can try creating there on a directory where you have permission to write and then copying it the the external drive.