Thanks Dave-in-Decatur,
Appologize, I also notice I posted the issue in Android, where it all started in 'Windows'.
I did some additional tests. Out of my 7700 Notes, approx. 600 Notes have been duplicated.
When I now delete/change a note, it is correctly sync. between the (1) Android version; (2) Web verison and (3) Windows version.
I could of course delete manually those remaining duplicated Notes. But I lost all my trust in Evernote.
Who tells me this will not happen again either tomorrow, next week or next year ?
I have also submitted a request towards the Helpdesk. Received pritty quick a 'standard' email with suggestions. After explaining that these didn't worked, no response yet... 😞
Additionally, when trying to backup (either Enex or Multiple Webpages), it is crashing. Sometimes at 50% completed but also in one case at 88%.
Is there a way to restore towards yesterday's database position ?