Verify that a disk image’s data isn’t corrupted using Disk Utility on Mac
The data in a disk image can be corrupted if a problem occurs while it’s being copied or if someone modifies it. You can see whether a disk image’s data has been corrupted by verifying its checksum, which is a calculation of all of its data. When a disk image is created, a checksum is computed and stored with the image. When you open the disk image, a checksum can be computed again and checked against the stored checksum. If the two checksums match, the disk image’s data hasn’t been corrupted.
You can choose when to compute and verify checksums. Be aware that doing so can take a long time.
In the Disk Utility app on your Mac, choose Images > Verify, then select the disk image that you want to verify.
Click Verify, then click Done.