{"id":"external-drives.why-is-my-external-drive-read-only","url":"/faq/external-drives/why-is-my-external-drive-read-only","category":{"id":"external-drives","title":"External drives"},"subcategory":{"id":"formats","title":"Drive formats"},"question":"Why is my external drive read-only on my Mac?","alt_questions":["Can't write to external drive Mac","External SSD is read only","Drive is not writable Storage Studio","You can only read this disk","mac external drive read only fix","Why can't I copy files to my external drive?"],"short_answer":"Usually it's NTFS (read-only on a Mac), macOS mounted it read-only after finding errors (run First Aid), a permissions setting in Get Info, or a lock switch. Storage Studio needs a writable drive.","answer_markdown":"The most common reasons:\n\n- **It's NTFS** — macOS reads Windows NTFS drives but can't write to them. Erase it as APFS (after backing up) to use it.\n- **macOS found file-system errors** and mounted it read-only to protect your data — run **First Aid** in Disk Utility.\n- **Permissions** — in Finder, choose **Get Info** on the drive and check the Sharing & Permissions section.\n- **A physical lock switch** on some SD cards and older drives.\n\nStorage Studio needs to write to the drive, so a read-only drive can't be set up or used for moves; the speed test will also fail on it.","answer_html":"

The most common reasons:

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Storage Studio needs to write to the drive, so a read-only drive can't be set up or used for moves; the speed test will also fail on it.

","answer_text":"The most common reasons:\n\n- It's NTFS — macOS reads Windows NTFS drives but can't write to them. Erase it as APFS (after backing up) to use it.\n- macOS found file-system errors and mounted it read-only to protect your data — run First Aid in Disk Utility.\n- Permissions — in Finder, choose Get Info on the drive and check the Sharing & Permissions section.\n- A physical lock switch on some SD cards and older drives.\n\nStorage Studio needs to write to the drive, so a read-only drive can't be set up or used for moves; the speed test will also fail on it.","tags":["read-only","ntfs","permissions","troubleshooting"],"related":[{"id":"external-drives.can-i-use-an-ntfs-drive","question":"Can I use an NTFS-formatted drive from a Windows PC?","url":"/faq/external-drives/can-i-use-an-ntfs-drive"},{"id":"external-drives.what-is-ignore-ownership-on-this-volume","question":"What is \"Ignore ownership on this volume\" on my external drive, and does it matter?","url":"/faq/external-drives/what-is-ignore-ownership-on-this-volume"},{"id":"external-drives.does-storage-studio-work-with-an-encrypted-external-drive","question":"Does Storage Studio work with an encrypted external drive?","url":"/faq/external-drives/does-storage-studio-work-with-an-encrypted-external-drive"}],"applies_to":"all","last_reviewed":"2026-10-01","title":"Why is my external drive read-only on my Mac? — Storage Studio FAQ","description":"Usually it's NTFS (read-only on a Mac), macOS mounted it read-only after finding errors (run First Aid), a permissions setting in Get Info, or a lock switch. Storage Studio needs a writable drive.","crumbs":[{"name":"Home","path":"/"},{"name":"FAQ","path":"/faq/"},{"name":"External drives","path":"/faq/external-drives/"},{"name":"Why is my external drive read-only on my Mac?","path":"/faq/external-drives/why-is-my-external-drive-read-only"}],"jsonld":{"@context":"https://schema.org","@type":"FAQPage","url":"https://storagestudio.us/faq/external-drives/why-is-my-external-drive-read-only","inLanguage":"en","dateModified":"2026-10-01","mainEntity":[{"@type":"Question","name":"Why is my external drive read-only on my Mac?","alternateName":["Can't write to external drive Mac","External SSD is read only","Drive is not writable Storage Studio","You can only read this disk","mac external drive read only fix","Why can't I copy files to my external drive?"],"acceptedAnswer":{"@type":"Answer","text":"The most common reasons:\n\n- It's NTFS — macOS reads Windows NTFS drives but can't write to them. Erase it as APFS (after backing up) to use it.\n- macOS found file-system errors and mounted it read-only to protect your data — run First Aid in Disk Utility.\n- Permissions — in Finder, choose Get Info on the drive and check the Sharing & Permissions section.\n- A physical lock switch on some SD cards and older drives.\n\nStorage Studio needs to write to the drive, so a read-only drive can't be set up or used for moves; the speed test will also fail on it.","url":"https://storagestudio.us/faq/external-drives/why-is-my-external-drive-read-only"}}]},"fragment":"
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External drives · Drive formats

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Why is my external drive read-only on my Mac?

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Short answer: Usually it's NTFS (read-only on a Mac), macOS mounted it read-only after finding errors (run First Aid), a permissions setting in Get Info, or a lock switch. Storage Studio needs a writable drive.

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The most common reasons:

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  • It's NTFS — macOS reads Windows NTFS drives but can't write to them. Erase it as APFS (after backing up) to use it.
  • macOS found file-system errors and mounted it read-only to protect your data — run First Aid in Disk Utility.
  • Permissions — in Finder, choose Get Info on the drive and check the Sharing & Permissions section.
  • A physical lock switch on some SD cards and older drives.
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Storage Studio needs to write to the drive, so a read-only drive can't be set up or used for moves; the speed test will also fail on it.

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Last reviewed

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Related questions

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