Hey @Carlo C.10 - thanks for bringing this to our attention.
Could you try the most recent version of the Dropbox desktop app directly from this page and let me know how it goes?
Also make sure that you've granted Dropbox full disk access as outlined here.
For more information on the external drive support for Dropbox on File Provider, you can take a look at this help center article.
Keep me posted with any updates!
", "bodyPlainText": "Hey @Carlo C.10 - thanks for bringing this to our attention. \nCould you try the most recent version of the Dropbox desktop app directly from this page and let me know how it goes?\nAlso make sure that you've granted Dropbox full disk access as outlined here. \nFor more information on the external drive support for Dropbox on File Provider, you can take a look at this help center article.\nKeep me posted with any updates!", "recordID": 868862, "categoryID": 57, "siteID": 6038715, "name": "Re: Error 513 (NSCocoaErrorDomain) when selecting an encrypted APFS external drive \u2013 Dropbox 274.4.4905", "url": "https://community.dropbox.com/en/discussion/comment/868862#Comment_868862?utm_source=community-search&utm_medium=organic-search&utm_term=%22274.4.4905%22", "dateInserted": "2026-10-26T06:55:10+00:00", "breadcrumbs": [ { "name": "Home", "url": "https://community.dropbox.com/" }, { "name": "English Community", "url": "https://community.dropbox.com/en/categories", "recordID": 2 }, { "name": "Help", "url": "https://community.dropbox.com/en/categories/help", "recordID": 3 }, { "name": "Apps and Installations", "url": "https://community.dropbox.com/en/categories/apps-and-installations", "recordID": 57 } ], "insertUserID": 364291, "isForeign": false, "discussionID": 862084, "siteDomain": "https://community.dropbox.com", "searchScore": 23.374269999999999 }, { "recordType": "comment", "type": "answer", "legacyType": "Answer", "body": "Thanks Jay - yes - full disk access, plus device control and data access.
OS is MacOS 27.01 (26A434) and Dropbox version is 274.4.4905
No different error messages that I'm aware of, though here are the logs (from .dropbox/logs) from the latest external drive attempt after checking that and rebooting.
[Removed as per Community Guidelines]
Thanks
", "bodyPlainText": "Thanks Jay - yes - full disk access, plus device control and data access.\nOS is MacOS 27.01 (26A434) and Dropbox version is 274.4.4905\nNo different error messages that I'm aware of, though here are the logs (from .dropbox/logs) from the latest external drive attempt after checking that and rebooting.\n[Removed as per Community Guidelines]\n\nThanks", "recordID": 868483, "categoryID": 57, "siteID": 6038715, "name": "Re: The Dropbox Desktop app won't start on a new installation with an external drive on Mac OS", "url": "https://community.dropbox.com/en/discussion/comment/868483#Comment_868483?utm_source=community-search&utm_medium=organic-search&utm_term=%22274.4.4905%22", "dateInserted": "2026-10-14T12:50:22+00:00", "dateUpdated": "2026-10-14T12:54:50+00:00", "breadcrumbs": [ { "name": "Home", "url": "https://community.dropbox.com/" }, { "name": "English Community", "url": "https://community.dropbox.com/en/categories", "recordID": 2 }, { "name": "Help", "url": "https://community.dropbox.com/en/categories/help", "recordID": 3 }, { "name": "Apps and Installations", "url": "https://community.dropbox.com/en/categories/apps-and-installations", "recordID": 57 } ], "insertUserID": 1948328, "updateUserID": 330248, "isForeign": false, "discussionID": 862007, "siteDomain": "https://community.dropbox.com", "highlight": "OS is MacOS 27.01 (26A434) and Dropbox version is 274.4.4905\nNo different error messages that I'm aware of, though here are the logs (from .dropbox/logs) from the latest external drive attempt after checking...", "searchScore": 22.412213999999999 }, { "recordType": "comment", "type": "answer", "legacyType": "Answer", "body": "Hi Walter and I_R_H,
I am experiencing what appears to be the same issue on macOS 27.0.1, with Dropbox versions 274.4.4905 and 275.4.3565.
Dropbox starts and works normally when its folder is on the internal SSD. However, selecting an external drive during setup causes Dropbox to fail to start with NSCocoaErrorDomain Code 513 (permission denied).
I have reproduced this with two separate external NVMe SSDs and a newly created APFS (Encrypted) volume. Full Disk Access has already been granted to Dropbox, and reinstalling the app has not resolved the issue.
The traceback points to _init_completion_inner in Dropbox's macOS File Provider handler (file_provider.py), which appears to match the failure reported in this thread.
Could you please include this report in the ongoing investigation and let me know whether there is a known workaround or a fix planned? I can provide further diagnostic information privately through Dropbox Support if needed.
Thank you.
", "bodyPlainText": "Hi Walter and I_R_H,\nI am experiencing what appears to be the same issue on macOS 27.0.1, with Dropbox versions 274.4.4905 and 275.4.3565.\nDropbox starts and works normally when its folder is on the internal SSD. However, selecting an external drive during setup causes Dropbox to fail to start with NSCocoaErrorDomain Code 513 (permission denied).\nI have reproduced this with two separate external NVMe SSDs and a newly created APFS (Encrypted) volume. Full Disk Access has already been granted to Dropbox, and reinstalling the app has not resolved the issue.\nThe traceback points to _init_completion_inner in Dropbox's macOS File Provider handler (file_provider.py), which appears to match the failure reported in this thread.\nCould you please include this report in the ongoing investigation and let me know whether there is a known workaround or a fix planned? I can provide further diagnostic information privately through Dropbox Support if needed.\nThank you.", "recordID": 868610, "categoryID": 57, "siteID": 6038715, "name": "Re: The Dropbox Desktop app won't start on a new installation with an external drive on Mac OS", "url": "https://community.dropbox.com/en/discussion/comment/868610#Comment_868610?utm_source=community-search&utm_medium=organic-search&utm_term=%22274.4.4905%22", "dateInserted": "2026-10-16T16:37:04+00:00", "breadcrumbs": [ { "name": "Home", "url": "https://community.dropbox.com/" }, { "name": "English Community", "url": "https://community.dropbox.com/en/categories", "recordID": 2 }, { "name": "Help", "url": "https://community.dropbox.com/en/categories/help", "recordID": 3 }, { "name": "Apps and Installations", "url": "https://community.dropbox.com/en/categories/apps-and-installations", "recordID": 57 } ], "insertUserID": 1948380, "isForeign": false, "discussionID": 862007, "siteDomain": "https://community.dropbox.com", "highlight": "Hi Walter and I_R_H,\nI am experiencing what appears to be the same issue on macOS 27.0.1, with Dropbox versions 274.4.4905 and 275.4.3565....", "searchScore": 21.672314 }, { "recordType": "discussion", "type": "question", "legacyType": "Question", "body": "Hi - I've been looking to switch my Dropbox location to an external drive on my Mac, but having problems getting this to work ('Could't Start Dropbox) after a few iterations with various troubleshooting, such as an advanced reinstall. Installing with a default location works fine.
I'm on File Provider (as described here), and I've followed the instructions here - I've signed out, set-up the drive with APFS (Encrypted) - a new partition on an external drive, signed in and gone through the start-up wizard. In the advanced settings, it lets me select my external drive, but then throws an error on start-up - see pop-up and error codes below.
I've changed the permissions on the external drive as a test, but this did not help.
Any suggestions? The only other thought/question I had was for the advance reinstall instructions for File provider, did the terminal for the line below need to be updated to reflect the '~/Library/CloudStorage/Dropbox' path?:
sudo mv ~/.dropbox ~/.Trash/dropbox.old
Thanks.
\n \n \n![\"image.png\"](\"https://community.dropbox.com/home/leaving?allowTrusted=1&target=https%3A%2F%2Fca.v-cdn.net%2F6038715%2Fuploads%2F2SYQ3OHZKGHT%2Fimage.png\")
\n \n\nError Code is:
bn.BUILD_KEY: Dropbox
\nbn.VERSION: 274.4.4905
\nbn.constants.WINDOWS_SHELL_EXT_VERSION: 97
\nbn.is_frozen: True
\nmachine_id: dd41a4a9-3bbf-5475-a857-ccc86d93e6b8
\npid: 4507
\nppid: 1
\nuid: 501
\nuser_info: pwd.struct_passwd(pw_name='[Removed as per Community Guidelines]', pw_passwd='', pw_uid=501, pw_gid=20, pw_gecos='[Removed as per Community Guidelines]', pw_dir='[Removed as per Community Guidelines]', pw_shell='/bin/zsh')
\neffective_user_info: pwd.struct_passwd(pw_name='[Removed as per Community Guidelines]', pw_passwd='', pw_uid=501, pw_gid=20, pw_gecos='[Removed as per Community Guidelines]', pw_dir='[Removed as per Community Guidelines]', pw_shell='/bin/zsh')
\neuid: 501
\ngid: 20
\negid: 20
\ngroup_info: grp.struct_group(gr_name='staff', gr_passwd='', gr_gid=20, gr_mem=['root'])
\neffective_group_info: grp.struct_group(gr_name='staff', gr_passwd='', gr_gid=20, gr_mem=['root'])
\nDYLD_LIBRARY_PATH: None
\ncwd: '/'
\nreal_path='/'
\nmode=0o40755\tuid=0\tgid=0
\nparent\tmode=0o40755\tuid=0\tgid=0
\nHOME: '[Removed as per Community Guidelines]'
\nappdata: '[Removed as per Community Guidelines]/.dropbox/instance1'
\nreal_path='[Removed as per Community Guidelines]/.dropbox/instance1'
\nmode=0o40700\tuid=501\tgid=20
\nparent\tmode=0o40755\tuid=501\tgid=20
\ndropbox_path: None
\nnot found
\nparent\tnot found
\nsys_executable: '/Applications/Dropbox.app/Contents/MacOS/Dropbox'
\nreal_path='/Applications/Dropbox.app/Contents/MacOS/Dropbox'
\nmode=0o100755\tuid=501\tgid=20
\nparent\tmode=0o40755\tuid=501\tgid=20
\ntrace.file: '/Applications/Dropbox.app/Contents/Resources/python-pypkg.zip/dropbox/client/ui/common/boot_error.pyc'
\nreal_path='/Applications/Dropbox.app/Contents/Resources/python-pypkg.zip/dropbox/client/ui/common/boot_error.pyc'
\nnot found
\nparent\tnot found
\ntempdir: '/var/folders/n0/8vy4px_d1kg5y_9s4nml4y9h0000gn/T'
\nreal_path='/private/var/folders/n0/8vy4px_d1kg5y_9s4nml4y9h0000gn/T'
\nmode=0o40700\tuid=501\tgid=20
\nparent\tmode=0o40755\tuid=501\tgid=20
\nTraceback (most recent call last):
\nFile \"desktop/dropbox/client/main.py\", line 7464, in _setup_root_for_account
\nFile \"desktop/dropbox/sync_root/helpers.py\", line 204, in create_root_for_account
\nFile \"desktop/dropbox/foundation/futures/basic.py\", line 939, in result
\nFile \"desktop/dropbox/exception/exception_decorators.py\", line 47, in newfn
\nFile \"desktop/dropbox/sync_root/handlers/macos/file_provider.py\", line 349, in _completion_domains
\nFile \"desktop/dropbox/sync_root/handlers/macos/file_provider.py\", line 335, in set_result_or_convert_exception
\nFile \"desktop/dropbox/foundation/futures/basic.py\", line 751, in set_result
\nFile \"desktop/dropbox/foundation/futures/basic.py\", line 714, in _on_post
\nFile \"desktop/dropbox/foundation/futures/basic.py\", line 1138, in _stage1
\nFile \"desktop/dropbox/foundation/futures/basic.py\", line 998, in _when_done
\nFile \"desktop/dropbox/foundation/futures/basic.py\", line 1157, in _stage2
\nFile \"desktop/dropbox/foundation/futures/basic.py\", line 751, in set_result
\nFile \"desktop/dropbox/foundation/futures/basic.py\", line 714, in _on_post
\nFile \"desktop/dropbox/foundation/futures/basic.py\", line 1119, in _stage1
\nFile \"desktop/dropbox/foundation/futures/basic.py\", line 451, in _then_callback
\nFile \"desktop/dropbox/sync_root/handlers/macos/file_provider.py\", line 1286, in _init_completion
\nFile \"desktop/dropbox/exception/exception_decorators.py\", line 47, in newfn
\nFile \"desktop/dropbox/sync_root/handlers/macos/file_provider.py\", line 1207, in _init_completion_inner
dropbox.mac.internal.MacError: [Errno 513] Error Domain=NSCocoaErrorDomain Code=513 \"The file couldn\u2019t be saved because you don\u2019t have permission.\"