If you go into your settings for OneDrive, you can select which folders should be synced https://support.microsoft.com/en-us/office/choose-which-onedrive-folders-to-sync-to-your-computer-98b8b011-8b94-419b-aa95-a14ff2415e85

I believe the green check marks mean you chose to keep only online.

Click on the OneDrive icon on the lower right tray and view. your sync client and see what you have that is set to sync or not.

OneDrive is not designed to sync every local files as the current user logon to Windows 10 will normally not having permission for all files and folders inside a sync location and it is also the reason why you cannot select the folder for the backup utility.

If you want to do a full backup, it is better to use utility like Acronis to do the magic.

For OneDrive, I have a single local folder selected, and under which folder, I have my everything - including my Desktop files that I have mapped with RegEdit.

So, within this single folder, I have many-many sub-folders and files with different status icons.

When I hover over OneDrive, I see...


... but I still see


So, you will see that my C# folder is "Sync Pending, and is going back to 2020. I have not touched this folder since that time, and I have no idea how many other folders are not synched.

Contrary to what I said yesterday, Win 10's Backup now lets me select OneDrive's folder.
 

...But, why can't I set a time of day, like 7 pm, as I don't want to slow down the PC During working hours?

Also, it allowed me to select an external drive - where to store the backup, but not the target folder?

This said, is it still worthwhile to invest in another Backup utility, like Acronis? Will it let me select to backup OneDrive, web folderse, and specify an external drive/folder?

I'm not sure if I can invest in ongoing cloud backup costs, especially as I have so many external drives lying around.

How can I check the quality of a drive?

Thanks!

You have two issues and let's stick to one :)  Otherwise it gets confusing.

For OneDrive, in your settings, click on the account tab and then select Choose Folders. There you can see what folders you have in OneDrive that are available both online and offline.



You can also select to have your Desktop, Documents and Images sent to your OneDrive
https://support.microsoft.com/en-us/office/back-up-your-documents-pictures-and-desktop-folders-with-onedrive-d61a7930-a6fb-4b95-b28a-6552e77c3057?ui=en-us&rs=en-us&ad=us


That should really cover you.  As for backing up, the Acronis option is only $50 per year https://www.acronis.com/en-us/products/true-image/.  I feel your files are safer there than an external hard drive, especially if it is more than a few years old. When I used an external HD, I changed mine every couple of years because the last thing you want is that to fail.  Now I rely 100% on using the cloud.

Under Setting, C# is checked

When I drill down, I noticed that only temp files are blocked.

So, do I have to resolve all manually until I get all green checks?

Besides this, do you also recommend Acronis, and why?

I thought OneDrive keeps deleted files for 30 days plus version control.

I misspoke, when I drill down other folders with a Synch Pending icon, all sub-items have a green checkmark - so there's nothing to fix. I'm also viewing hidden files.