Mac OS: OneDrive uses up System Drive Storage Even With Files On Demand Selected Set to Download As You Use Them

Question

I admit to always being a little confused how OneDrive works even on a PC but I'm completely baffled by it on my Mac.

Currently I have all my docs etc in iCloud and I want to move them to OneDrive. I don't want the files to be on my local system drive, just on OneDrive like I had it with iCloud.

So in Finder, I dragged files from iCloud and dropped them into OneDrive. I then found that whilst the files were on OneDrive, verified by viewing them online, they were also on my System Drive as all the free space on it had been filled up. In OneDrive preferences I went to Account>Choose Folders and unchecked all the folders. These then disappeared from Finder and the disc space slowly re-appeared. Once the disc space returned, I rechecked all the folders, they all appeared in Finder again but this time the System Disc Space wasn't used up.

I then went to upload another folder from an external USB drive to OneDrive. As soon as I set this copying I could see it was adding it to the system drive. It's currently in the process of uploading 120GB and has used 120GB of space on my system drive. I'm presuming and hoping that if I uncheck and recheck the folder in preferences it will free up the space on the system drive as before but surely this can't be normal operation?

How can I get it so that if I add a file to OneDrive it just goes to OneDrive and not to OneDrive and the System Drive especially when I have Files On Demand set to Download As You Use Them?

Answer 1

Hello Oliver,

Welcome to the Microsoft Community. Thank you for your detailed description, I understand that you are experiencing some confusion when using OneDrive on your Mac.

If you are expecting to transfer files from iCloud to OneDrive, the best way to do it is to download them locally and upload them to OneDrive manually one by one, so that you can monitor the transfer progress more easily and it is the most stable and secure. After making sure all your files are transferred properly, you can now consider removing them in iCloud.

For the issue of OneDrive files taking up your local disk, this is usually related to one of two reasons.

1. This can be due to unsuccessful settings related to the File Randomization, which may still be saved locally on the device. When you go to Preferences->Accounts->Select Folders and uncheck the folders here, the unchecked folders will not show up on your computer or OneDrive, so you will notice that the storage is cleared out, and when you check the folders again, this may reset the File On Demand settings so that the files are only present in the cloud and are not kept locally. Or you may have selected “Online only”, but since accessing files online may generate some local cache, you may notice some disk hogging. In this case, you may want to consider turning on “Free up space” for the entire OneDrive folder, making sure that File Randomization is turned on correctly.

Open Finder -> find OneDrive in the left-hand navigation, right-click on it, and select “Free up space”, which will save all OneDrive files only in the cloud and not locally. Now check your Mac's storage footprint again to see if it's changed.

2. It's also worth noting that the storage footprint on OneDrive for Apple (iPhone, iPad & Mac) is a long-standing issue that is by design, and may be related to the file system used by Apple systems. On Apple devices, online-only files in OneDrive sometimes still take up space. Apple devices may cache more file information to improve access speed, which may cause online-only files to take up more local storage space.

If the problem persists after ensuring that File On Demand is properly set to “Free up space”, consider reinstalling OneDrive to reset it, which will also reset the storage footprint (reinstalling will not affect any files that have been successfully synchronized).

I hope this is useful and please feel free to ask any questions.

Best regards,

Ian - MSFT | Microsoft Community Support Specialist