A Microsoft file hosting and synchronization service.
Hi omerz1995,
Greetings. Thank you posting the thread to our community.
I understand your concern, it seems you want to safely store all you OneDrive contents and without concern about they’ll be not synced.
Based on your description, as you mention:” I have a folder that is 8.4GB (as shown in the online version of OneDrive) but it's syncing only 5.59GB of storage” and you also mention this folder has around 12,000 files. In that case, which I assume your OneDrive shows a “Processing changes”, if yes, then you don’t need to make any changes, OneDrive will upload all files, but this may take some time if your internet speed is slow.
For the query:” Is there any way to safely download and store all my onedrive content”,
Generally, with OneDrive Files On-Demandwe can store our OneDrive files locally to make them available offline. You can select the folder you want and right-click it, then select “Always keep on this device”, when you see the files that have the green circle with the white check mark, it means these files are downloaded to the local and available even when you’re offline.
Note: You need to turn on the Files On-Demand to use this feature.
Here is a screenshot of my test results of store OneDrive folder locally, as the result shows the file in the folder also present the same status as the folder itself:
Here are the official support articles as reference for you: Save disk space with OneDrive Files On-Demand for Windows - Microsoft Support, Fix OneDrive sync problems - Microsoft Support
Meanwhile, I’d like to confirm whether there is any error messages pop-up when you try to sync your OneDrive content and what’s your OneDrive icon looks like when you syncing your OneDrive. If yes, Please share your results and provide a full screenshot to me.
Looking forward to your reply, I’m glad to help you.
Appreciate for your patience and understanding.
Hope you having a nice day.
Sincerely,
Harry | Microsoft Community Moderator