It seems that some files (or name thereof) are "ineligible" for iCloud drive. For example, if the file name ends with a tilde, it cannot be uploaded to iCloud drive. [Example of programs that produce file names with tilde are Emacs (for back files) and RCS (for revision files).]

Has Apple published any reference on what is (or is not) "eligible" in iCloud drive?

  • 3
    Asked on ASC, highly voted but no replies.
    – grg
    Sep 9 '17 at 10:33

This is not an answer but here is a partial list of kind of file names that are considered ineligible for iCloud drive.

Warning: this list is purely based on trial and error on macOS 10.12.16. As of now, there does not appear to be an official documentation on this. So this behaviour may change in future.

  • Filenames with an extension and ending with tilde. (regex: .*\..*~)

  • Filenames ending with .tmp

  • Filenames starting with ~$

  • Filenames starting with .~

  • Directories named tmp

  • Any folder or file named dropbox or Dropbox or OneDrive.

It seems that iCloud drive tries to identify temporary files by their names and does not upload them into the clouds.

10/31/2021 Verified dropbox and onedrive were marked ineligible. Changed them to dbx and odr and they backed up. Now I'm switched to Apple ecosystem.


Files over 50 GB are ineligible. From official iCloud Drive FAQ:

You can store any type of file in iCloud Drive, as long as it's 50GB or less in size (…).

  • Well that explains why my 59.25GB file is listed as ineligible. Thanks!
    – somehume
    Aug 24 '19 at 6:37

So answer the yes / no question you asked. No - Apple hasn't published a detailed specification listing what does and does not sync. Apple does say

You can store any type of file in iCloud Drive, as long as it's 50GB or less in size and you don't exceed your iCloud storage limit...

You shouldn't store app folders, libraries, or .tmp files in iCloud Drive.

The last sentence is curious since "shouldn't" could run from "don’t recommend" to "we actively block" and those aren't precisely the same experience.

This list of what’s included or excluded by rule isn't published for Time Machine - so there's a long history of Apple implementing and shipping systems that back up and sync files which have engineered inclusions and exclusions, but not explicitly documenting the details publicly.

Some other questions attempt to reverse-engineer and document what's implemented, though.


there are 2 name extensions that will stop iCloud syncing.

  • .nosync
  • .tmp

if you add .nosync to a folder name you will need to add it also to the folder contents.

if you add .tmp to a folder name it'll stop syncing the folder & its contents.

I'm able to sync files greater than 50GB so not sure if anything has changed since the 50GB limit mentioned in the apple doc.

File size greater than 50GB

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