We have a Mac running 10.12.6
It connects to our SBS 2011 Server shares using SMB (CIFS makes no difference to the issue). For some reason Finder keeps forgetting that the user has permissions to access files and folders on the share.
For example if I have a Finder window open containing a few documents, I open a document, minimise Finder and do some work and then after a while I go back to the Finder window, I'll find I've been kicked out of it and forced up one level in the folder hierarchy. In that upper level I'm presented with stop signs and no permissions to open any of those folders or files. If I then go up one more level (or close the Finder window if there are no more levels) and then come back to where I want to be, permissions are restored.
The Mac doesn't seem to be losing a connection to the share, it just seems to forget the assigned permissions.
Other than the AD join for user login the Mac is 100% local and that share is simply mounted upon login.
In SBS Console. The share permissions are set to 'Everyone' and the Everyone group has full control. Then we split users into Security Groups and the security group is assigned full control at the folder level where needed.
Does anyone have any idea what's going on? This seems to be a Sierra based change.