Hi - My scenario is a school with approx 500 users and 30 teachers - It constantly happens that folders are changed to "read-only and or hidden". Teachers have access to these folders and need to read and change files. Is there a way in which users can accidentally change the status of folders - or is there a virus that can do this - or a shortcut on the keys.

Hi, Generally we will not change the "hidden" or "read only" attribute by accident. If there is no security program installed, it is recommended to get a full scan incase it is caused by virus. You can try to cancel the read only and hidden attribute first, then apply following steps to restrict the permission to change these settings. 1. Find the root folder shared to public, right click on it and choose Properties. 2. Go to Security tab, click Advanced. 3. On Permission tab and click Change Permissions. 4. Highlight the group (maybe you shared to Everyone), click Edit. 5. Uncheck the boxes including "Write extended attributes" and "Write attributes". Also uncheck "Change permissions". 6. Click OK. This should help avoid change these attributes by mistake. If same issue still happening, check who has the permission to do such thing (such as local Administrators group)