Save to Disk Image does not warn when macOS dmg not found

[Dave Lebbing]

If a macOS disk image is selected and then later is moved, when clicking Save to Disk Image, no warning is shown that the macOS dmg was not found. The resulting MDS dmg will then be missing the required macOS dmg and will fail when deployed.

This does not appear to be an issue for Save to Volume, which will warn when macOS dmg not found.

[timothy perfitt]

thanks!

[timothy perfitt]

added checks and dialog if image is moved.

[Dave Lebbing]

Missing macOS dmg warning shows at the end of the saving process for "Save to Disk Image". For "Save to Volume" the warning is shown at the beginning before trying to save anything. Would be better for both to warn immediately.

Also, warning message text could benefit from adding text shown in bold here:

Please select a different macOS disk image or return the macOS disk image back to this location

[timothy perfitt]

changed text. moving is harder dialog so punting for now.