Error message "Root element missing" while trying to open a saved workflow

[San]

I am getting this error message and the workflow is not opening, neither is there a auto-recovered version showing under Files>Open Auto recovered files.

I want to know what causes this issue and what is the fix. 

[patrick_digan]

@San If you right click on the workflow in file explorer, use the open with button to open it in notepad/notepad++. Can you post the snippet of the top section. For example, here is what a workflow looks like: