Image Format: Select read/write disk image so you can read from and write to the disk image at any time.Ĭlick Create and you’ll be prompted to create an encryption password for your disk image.

Partitions: Select Single partition – Apple Partition Map to use a single partition inside your disk image file.

If you’re encrypting sensitive files, you’ll probably want to choose 256-bit and accept the slight slow-down for more security.

256-bit is more secure, while 128-bit is faster. Encryption: Choose either 128-bit or 256-bit AES encryption.Format: Select Mac OS Extended (Journaled) as the file system.You can enlarge or shrink the disk image later. The container file will take up the maximum file size immediately - so, if you choose 100 MB, it will take 100 MB of space on your hard drive even if you have no files saved inside it yet.

For example, if you choose 100 MB, you’ll only be able to store up to 100 MB of files inside it. Size: Choose a size for your disk image file.This name is more of a description - it will appear as the name of the container when the file is mounted. Name: Enter a name for the disk image file.For example, if you name it “MyImage”, the container file will be saved on your hard drive as a file named MyImage.dmg. Save As: Provide a file name for the disk image file.Here are the options you’ll need to configure: This will create a new disk image (.dmg) file. You can also just press Command+Space to open Spotlight search, type Disk Utility, and press Return to open it.Ĭlick New Image on the toolbar in the Disk Utility window. Open a Finder window, click Applications in the sidebar, double-click the Utilities folder, and double-click Disk Utility. To get started, you’ll need to open the Disk Utility application. Whenever you want to lock access to your files, you can unmount the image file. Whenever you want to access your files, you can “mount” the image file and provide your password.

You can create an encrypted disk image using the built-in Disk Utility. Macs don’t need third-party utilities like TrueCrypt to create a secure, encrypted container for your sensitive files.

Mac disk image increase space