Deleted files/folders reappear as they are synced back online from client OneDrive

Hi Arvi10 - my reply above showing guessing how Dropbox or Google Drive handles deletions may give a hint of the root cause but I can confirm without a shadow of a doubt that the following happens on OneDrive:

1. Logon to a computer where you had OneDrive synchronised but haven't logged onto for a while - say a few months
2. OneDrive will restore deleted folders and files back to the last time you logged on

Fortunately, thank goodness, it doesn't overwrite edited versions or delete anything. You do get the horrible "My file - LAPTOP046.ps1" cropping up where I assume it thinks it's got the latest version (it never has!) but there is a file there with a newer timestamp so it renames its (old) copy with the suffix and restores that. The creation of these files is usually my trigger to go into OneDrive and restore it back in time - a feature designed to Wannacry attacks but used because of this bug.

I suspect, but a lot of guessing, that this is because OneDrive doesn't keep a transaction log kind of structure along side the actual folders and files. Therefore when you logon to an old computer, it has no idea that "Monthly" was deleted on another system many days later and merrily brings it back.

Hence my observation that this is a fundamental flaw in the synchronisation algorithm used by OneDrive which Dropbox and Google Drive don't suffer from. They have a transaction log which they can refer to resolve issues like this.

So the Microsoft programmers need to go back to the drawing board IMO... wearing my developer hat. I am flabbergasted that OneDrive has this fundamental flaw and they intend you to use it for business! Thank goodness that my clients only tend to logon to one computer at once!