Hi! Burruburru,
Welcome to the Microsoft Community! I realize that you've encountered a problem with OneDrive files are being shared without your knowledge and I understand how you feel. I noticed that you have canceled your file sharing, and in fact, by canceling it, no one else will be able to see your files!
For now, I suggest you click on the link: OneDrive (live.com) >Log in to your OneDrive account and locate your files > Click on the three dots to the right of the file name > Click on Manage Permissions to check the sharing of your current files
As community members are only able to provide basic software technical support, we are unable to check who has opened a user's files, so I would suggest you try contacting the OneDrive team for further support. please click the link: email the OneDrive support team.
If the link above to send an email to the OneDrive team doesn't work, you can also contact the OneDrive team via OneDrive mobile on your cell phone as follows:
- If you are using an Android phone (the OneDrive mobile app can be found in the Google Play store): open OneDrive > click My > Help & Feedback at the bottom of the page.
- If you are using an iPhone (OneDrive mobile app available from the App Store): Please open OneDrive > click on your avatar on the left side of the page > click on Help and Feedback
Thank you for your understanding and patience.
Best Regards Eddy | Microsoft Community Support Specialist