How to make OneDrive sync to an external HDD under MacOS?

Question

The question is in the title. Microsoft gives these instructions, however the part for Mac is either obsolete or just never worked (and looks unfinished to be honest). No matter which file system I format the drive to (tried exFAT / APFS / APFS (Case Sensitive)) OneDrive keeps complaining that the destination needs to be non-removable and case-insensitive:

And actually Microsoft predicted that such error might appear, giving a couple of extra steps to ensure compatibility at the very bottom of the page:

1. Open a Finder window on your Mac, then select Applications.

2. Ensure the external drive is a non-ejectable type and formatted as APFS. Learn how.

The first step does not make any sense to be honest, the second refers to Apple Documentation covering how to use the Disk Utility tool. Unfortunately this tool is not able to alter RMB bit of the device or MacOS's perception of external drive (to make it internal), so it doesn't really help.

It looks like the only viable option left is to flip the RMB bit right into the removable HDD driver, but i'd like to ensure that I'm not missing anything before implementing such a drastic change.

P.S. My mac has macOS Monterey (12.4) running.

Answer 1

I found a workaround to backup files on a removable hard disk to the OneDrive cloud.

1. The OneDrive folder is in the default location on the system disk.
2. I created a folder 'CloudBackup' within the OneDrive folder
3. Use rsync to backup the folder 'THISFOLDER' on the external disk 'HD_Data' to the OneDrive folder.
4. Use Applescript to run a shell script:

property tUSERNAME : short user name of (system info)

property tSOURCEFOLDER: "/Volumes/HD_Data/THISFOLDER/"

property tDESTFOLDER : "/Users/" & tUSERNAME & "/Library/CloudStorage/OneDrive-Personal/CloudBackup"

set tSCRIPT to "rsync -a --delete-after " & (quoted form of tSOURCEFOLDER) & " " & (quoted form of tDESTFOLDER)

do shell script tSCRIPT

5. Set the folder 'CloudBackup' to 'Free Up Space'. This tells OneDrive that after uploading to the cloud all files in the folder should not take up space on the system disk. This can be done manually in the Finder by right clicking on the folder and choose 'Free up Space' or with a script:

set tSCRIPT to "/Applications/OneDrive.App/Contents/MacOS/OneDrive /unpin /r ~/Library/CloudStorage/OneDrive-Personal/CloudBackup"

do shell script tSCRIPT

Another method for backing up files and folders on an external disk is to use rclone. Install rclone on Linux or Macos:

sudo -v ; curl https://rclone.org/install.sh | sudo bash

run rclone config to get credentials from Microsoft.

backup example:

/usr/local/bin/rclone sync '/Volumes//' 'myremote: