Found my Solution: Sharing file over SMB and Big Sur in Terminal sudo chmod +a "group:yourgroupname allow readsecurity,readattr,readextattr,list,search,read,execute,writeattr,writeextattr,delete,add_file,add_subdirectory,delete_child,write,append,file_inherit,directory_inherit" DirectoryNameToApplyACLTo Copy-paste the above line in a text or in Notes line is longer than appearing above Make sure quotes are Quotes ( " ) Try to make your group name without any space, it worked better for me. Drag and drop the folder in the terminal (DirectoryNameToApplyACLTo) to avoid mistakes Make sure there is a space between _inherit" and (DirectoryNameToApplyACLTo) In File Sharing Preference right-click the folder and Apply Permissions to Enclosed items. Test. Ex: groupe name: Test Folder name: Test2 Location: Guest / public / Test2 Terminal: sudo chmod +a "Test allow readsecurity,readattr,readextattr,list,search,read,execute,writeattr,writeextattr,delete,add_file,add_subdirectory,delete_child,write,append,file_inherit,directory_inherit" /Users/Guest/Public/test2  Thanks to https://community.spiceworks.com/topic/2184048-acls-permissions-and-file-sharing-in-mojave Thanks to Strontium90 for pointing me in the right direction. Apple is making it just a little harder than it was on OS 6.5 and a Mac plus! iTunes is gone iPhoto also Searching for a solution on the web used to be easy. Try searching for a duplicate in Music on Google!!! or duplicate in Photo on Google!!! Sharing files was also easy...With OS X Server With a little sauce, everything finally worked... I'm sure it will help someone else.

Hi Strontium90 , if you could give me a hand. You replied and help on this thread: https://discussions.apple.com/thread/250537136 since there is no direct way to contact someone I'm trying here you should see the comment. For weird reasons when copy-pasting terminal lines on the communities forum some chunks are missing. here is my email voycom at me.com I started I new tread but not getting any answer.... https://discussions.apple.com/thread/253002760 will delete this in a couple of days... Thank's in advance