@IvanFL if your OneDrive would support that and has worked in the past it might be something else. Please note that when putting KNIME workflows on a synced drive a lot of synchronization will go on, especially if you do a lot of editing. It might well be that some sort of sync conflict might arise. Maybe check for messages from the OneDrive console.
One idea could be to stop syncing while you work on a workflow and activate it again once you have closed KNIME.
If this problem persists you might want to create a Log file in DEBUG mode so we could further investigate