{"id":"mac-storage-basics.what-are-macintosh-hd-and-macintosh-hd-data","url":"/faq/mac-storage-basics/what-are-macintosh-hd-and-macintosh-hd-data","category":{"id":"mac-storage-basics","title":"Mac storage basics"},"subcategory":{"id":"storage-overview","title":"Checking your storage"},"question":"Why are there two volumes, Macintosh HD and Macintosh HD – Data?","alt_questions":["macintosh hd data what is it","two macintosh hd in disk utility","can I delete macintosh hd data","system volume and data volume mac","macintosh hd - data volume","why does disk utility show two drives"],"short_answer":"Macintosh HD is the sealed, read-only macOS system; Macintosh HD – Data holds your apps and files. They share the same space, and the Data volume must never be deleted.","answer_markdown":"Since macOS Catalina, your startup disk is split into two volumes in the same APFS container: **Macintosh HD** holds macOS itself and is read-only and sealed, and **Macintosh HD – Data** holds your apps, files and settings. Finder shows them as one drive, which is why you normally only see Macintosh HD.\n\nThey share the same free space, so there's nothing to resize and nothing to delete. **Never erase or delete the Data volume** — that is where everything you own lives.\n\nSee [APFS containers and volumes](/faq/mac-storage-basics/what-is-an-apfs-container-and-volume).","answer_html":"

Since macOS Catalina, your startup disk is split into two volumes in the same APFS container: Macintosh HD holds macOS itself and is read-only and sealed, and Macintosh HD – Data holds your apps, files and settings. Finder shows them as one drive, which is why you normally only see Macintosh HD.

\n

They share the same free space, so there's nothing to resize and nothing to delete. Never erase or delete the Data volume — that is where everything you own lives.

\n

See APFS containers and volumes.

","answer_text":"Since macOS Catalina, your startup disk is split into two volumes in the same APFS container: Macintosh HD holds macOS itself and is read-only and sealed, and Macintosh HD – Data holds your apps, files and settings. Finder shows them as one drive, which is why you normally only see Macintosh HD.\n\nThey share the same free space, so there's nothing to resize and nothing to delete. Never erase or delete the Data volume — that is where everything you own lives.\n\nSee APFS containers and volumes.","tags":["apfs","disk utility","volumes"],"related":[{"id":"mac-storage-basics.what-is-an-apfs-container-and-volume","question":"What's the difference between an APFS container and a volume?","url":"/faq/mac-storage-basics/what-is-an-apfs-container-and-volume"},{"id":"mac-storage-basics.why-does-my-256gb-mac-show-less-than-256gb","question":"Why does my 256 GB Mac show less than 256 GB of total storage?","url":"/faq/mac-storage-basics/why-does-my-256gb-mac-show-less-than-256gb"}],"applies_to":"all","last_reviewed":"2026-10-01","title":"Why are there two volumes, Macintosh HD and Macintosh HD – Data? — Storage Studio FAQ","description":"Macintosh HD is the sealed, read-only macOS system; Macintosh HD – Data holds your apps and files. They share the same space, and the Data volume must never be deleted.","crumbs":[{"name":"Home","path":"/"},{"name":"FAQ","path":"/faq/"},{"name":"Mac storage basics","path":"/faq/mac-storage-basics/"},{"name":"Why are there two volumes, Macintosh HD and Macintosh HD – Data?","path":"/faq/mac-storage-basics/what-are-macintosh-hd-and-macintosh-hd-data"}],"jsonld":{"@context":"https://schema.org","@type":"FAQPage","url":"https://storagestudio.us/faq/mac-storage-basics/what-are-macintosh-hd-and-macintosh-hd-data","inLanguage":"en","dateModified":"2026-10-01","mainEntity":[{"@type":"Question","name":"Why are there two volumes, Macintosh HD and Macintosh HD – Data?","alternateName":["macintosh hd data what is it","two macintosh hd in disk utility","can I delete macintosh hd data","system volume and data volume mac","macintosh hd - data volume","why does disk utility show two drives"],"acceptedAnswer":{"@type":"Answer","text":"Since macOS Catalina, your startup disk is split into two volumes in the same APFS container: Macintosh HD holds macOS itself and is read-only and sealed, and Macintosh HD – Data holds your apps, files and settings. Finder shows them as one drive, which is why you normally only see Macintosh HD.\n\nThey share the same free space, so there's nothing to resize and nothing to delete. Never erase or delete the Data volume — that is where everything you own lives.\n\nSee APFS containers and volumes.","url":"https://storagestudio.us/faq/mac-storage-basics/what-are-macintosh-hd-and-macintosh-hd-data"}}]},"fragment":"
\n
\n\n\n\n\n
\n
\n

Mac storage basics · Checking your storage

\n

Why are there two volumes, Macintosh HD and Macintosh HD – Data?

\n

Short answer: Macintosh HD is the sealed, read-only macOS system; Macintosh HD – Data holds your apps and files. They share the same space, and the Data volume must never be deleted.

\n

Since macOS Catalina, your startup disk is split into two volumes in the same APFS container: Macintosh HD holds macOS itself and is read-only and sealed, and Macintosh HD – Data holds your apps, files and settings. Finder shows them as one drive, which is why you normally only see Macintosh HD.

\n

They share the same free space, so there's nothing to resize and nothing to delete. Never erase or delete the Data volume — that is where everything you own lives.

\n

See APFS containers and volumes.

\n\n

Last reviewed

\n\n

Related questions

\n

Also available as Markdown and JSON.

\n
"}