Overwritting shared folders in iCloud Drive

Hi sdpraetere, 

Thank you for using Apple Support Communities. 

It appears that you have a question about sharing folders with iCloud Drive.You want to know about changes made to a file and if the folder owner has access to the original file. We want to help. To make sure that we are covering everything, please look at this article that talks about how to  Share folders with iCloud Drive - Apple Support

Also, this article has some additional information: Use iCloud File Sharing to share folders and documents with other iCloud users.

Please see from the article we provided “If you allow others to make edits, they can change the files and you see the updates the next time you open the files on your Mac.”

Hope that helps.

Best Regards!

sdpraetere wrote:

If a participant overwrites a folder, does the owner of the folder also lose access to the original folder?

They should not have the ability to alter a folder. Files only.