What do I do if the disk image data is corrupted?
Solution 1:
The error message means that the downloaded file is corrupt and can't be opened.
Re-download it and try opening it again. If it fails again, make sure that the download isn't being interrupted.
If you can obtain a checksum for the file, you can check it against your download by running openssl sha1 ~/path/to/download which will show the checksum for your download. Comparing the results should show if the file you downloaded matches what you should expect to download.