Admin and Access to AD Joined SMB File Share

When a File Share is created with AD authentication, the default user permission, groups is everyone. Any user with the UNC path to do the mapping will succeed as long as the user is a part of the same AD as that of the Gateway. When you check the NTFS permissions of the share mapped to a windows machine the default is Everyone Full Control.

File Share access permissions take precedence over Windows NTFS permissions. When Allowed and Denied Users and Groups lists is configured at the file share, then Windows ACLs will not grant any access that overrides those lists. The Allowed and Denied Users and Groups lists are evaluated before ACLs, and control which users can mount or access the file share. If any users or groups are placed on the Allowed list, the list is considered active, and only those users can mount the file share.

That said, I would suggest to check the File share access settings using the AWS Storage Gateway console and navigating to the File share or using the API DescribeSMBFileShares to see if you have any Allowed and Denied Users/Groups list configured. If so, clear the list and save the settings. Once the Share is back in "Available" state, try mapping the share and access it using a Domain user from the same AD the gateway belongs to.

Additional Ref:

1. https://docs.aws.amazon.com/filegateway/latest/files3/using-smb-fileshare.html
2. https://docs.aws.amazon.com/filegateway/latest/files3/edit-file-share-access-smb.html

If the above suggestion did not address the issue, please open a case with AWS support for further investigation. Thank You.