Hi Henrik,
Thank you for posting your requirement on the forum.
This going to involve both ADManager Plus and ADAudit Plus as,
Permissions for files and folders : ADManager Plus --> AD Reports --> NTFS Reports --> Permission for folders.
Members of the groups, who have permissions on the folders : ADManager Plus --> AD Reports --> Group Reports --> Group Membership.
Auditing who accessed the file/folder/file server for the last 6 months : ADAudit Plus.
We would be happy to assist you with a workaround on this. Do drop an email to support@admanagerplus.com referencing this post.