Offline File Synchronization – In Windows 7 the "Work Offline/Work Online" option button disappears from Windows Explorer after an offline / online transition and the Client Side Cache remains offline until the next restart of the computer
You have Windows 7 configured for offline file synchronization to synchronize content from network shares and have it available offline. Users notice that Windows 7 changes usually to offline mode; however Windows 7 does not switch back to online mode automatically after the network becomes available. Synchronization of the UNC path is not possible, and in the Sync Center no information is available for the offline file synchronization partnership.
If the user accesses network resources in Windows Explorer, some network resources are online and accessible; however when the user tries to access resources that have been made available offline, the offline content is displayed from the Client Side Cache. The user can create new files and change existing files, but these files remain in the local cache.
You provide a file share and subfolders for every user like in the following example:
A user with the appropriate permissions can access subfolders dir1 and dir2 but do not have permissions to view the content of the share ShareName$.
This behavior is caused by the way Windows Vista and Windows 7 handle remote file operations. The UNC path is parsed and every part is checked for availability. In the case described in the sections above, Windows Vista or Windows 7 checks for the prefix \\ServerName. If this is successful it checks if the \ShareName$\ is available. Due to missing access rights on this level, the remote file operation fails and the Client Side Cache (CSC) provides files from the offline content if the UNC path was made available offline.
To solve this issue with the offline file synchronization ensure that all parts of an UNC path are accessible by a user. On an UNC path like \\ServerName\ShareName$\dir1\dir2 the following permissions are required on ShareName$ when the user synchronizes the subfolder dir1:
Share level (SMB) Permissions for the offline files share ShareName$:
Minimum permissions required
Security group of users needing to put data on share.
In this example Everyone is removed from the share permissions and a global group containing the user account is used to set share level permissions.
NTFS permissions needed for the root folder ShareName$ for offline file synchronization:
Minimum Permissions Required
Full Control, Subfolders and Files Only
Security group of users that need to put data on share
List Folder/Read Data - This Folder, Subfolders and Files
Full Control, This Folder, Subfolders and Files
On the subfolders \dir1 and \dir2, the following permissions are required: NTFS permissions needed for the folders dir1 and dir2 for offline file synchronization:
Minimum permissions required
In Windows Vista and Windows 7, all remote file system access requests are channeled by the Multiple UNC Provider (MUP). MUP redirects the request to a network redirector (the UNC provider) that is capable to handle the remote file system request. For example, for SMB requests MUP redirects the request to the network provider LanmanWorkstation (ntlanman.dll). LanmanWorkstation calls the Workstation Service (svchost.exe) that calls the network redirector (mrxsmb.sys).
MUP performs a prefix resolution operation (IOCTL_REDIR_QUERY_PATH) request to the network redirector that is registered with MUP and capable for the type of request. This prefix resolution operation parses the UNC path and checks every part for availability. If the return message from the prefix resolution is STATUS_LOGON_FAILURE or STATUS_ACCESS_DENIED, the request fails and MUP states the UNC path as not accessible.
The Client Side Cache intercepts requests that are channeled to the network redirector. If the prefix resolution operation fails like described in the section above, CSC provides content from the local cache if the UNC path was made available offline before.
The behavior is outlined in detail on the following links:
Offline Files; Work Offline; Work Online; button; disappears; Windows Explorer; after; offline; online; transition; client side cache; remains offline; until the next boot; permissions; least; privilege; access; rights