This question sounds very basic, but I have not found the answer.

In disk utility I can add a new APFS volumes to an (external) disk. Does this operation affect data already on the disk?

I know that similar operations on windows and linux does not affect the data, but just to be sure, are there any existing documentation for macOS and APFS about this?

  • Are you using a Intel or Apple Silicon Mac? Jun 13, 2023 at 16:03
  • @DavidAnderson Apple Silicon.
    – Ma Joad
    Jun 13, 2023 at 16:34
  • 3
    The answer should be "no". But question is confused: 2nd para talks about adding volume, title says container. Which is it?
    – Gilby
    Jun 13, 2023 at 22:36

1 Answer 1


The answer is definitely NO. Unless you directly delete a partition or a volume, the data is not affected. A volume in APFS is like a partition, but it can resize to share space with other partitions, instead of the size being set at creation. A container holds ALL volumes and partitions and can not be deleted, only erased. There can not be more than one container on a drive.

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