Windows Tip Sheet

Managing Offline Files

Take command with CSC and Group Policy.

• By Don Jones
• 12/01/2004

One Windows feature I’m often questioned about by readers is Offline Files which, by the way, is also known as Client-Side Caching, or CSC. It’s important to know that alternate name because a lot of Microsoft Knowledge Base articles use it, so if you’re a regular Knowledge Base browser (tells you what kind of a life I have, huh?), searching on CSC can turn up some pretty interesting tips.

New and Improved!
Knowledge Base article 884739, for example, was recently published and talked about a brand-new version of the CSC command-line tool, which is used to manage CSC—okay, Offline Files—on client computers. The new version provides some cool new functionality that makes managing offline files just a tad easier. You will need to contact Product Support Services (PSS) to obtain the new tool, although I’m a bit unclear why it can’t just be a download from the Microsoft Web site.

The tool is CSCCMD, and it has several options for client-side caching management, such as:

• /ENABLE, which turns on CSC. Only local admins can use this switch.
• /DISABLE, which turns CSC off again. Again, only local admins can use it.
• /ENUM:\\Server\Share, which enumerates all files in the cache from the specified server and share. You can add a path, if you like, to be more specific: /ENUM:\\Server\Share\Folder\Subfolder, for example. Add /RECURSE to include subfolders. This is a keen way to see what files from a particular share are being cached by a client; you could use this in a batch file or logon script, saving the results to a text file, to generate a network-wide inventory of cached files.
• /DISCONNECT:\\Server\Share disconnects the client computer from the specified share so that the synchronization manager no longer tries to synchronize files from that share.
• /MOVESHARE:\\Server1\Share1 \\Server2\Share2 is complicated, but what it does is tell the offline files manager that the files which used to be on \\Server1\Share1 are now located on \\Server2\Share2. Offline Files updates the cache to mark files appropriately. This is a handy way of telling a disconnected client that its file sources have moved so that when the client goes to re-synch again, it can find everything.

There are nearly a dozen other command-line switches to check the CSC database, force caching of files, check the status of CSC, specify files to cache (what a great logon script trick—you tell the users’ computers which files will be cached so the users don’t have to), extract files from the cache, and so forth. Check it out.

Micro Tips Did you know that Windows will automagically cache files that are opened from network shares? You (or the user) can specify the maximum amount of disk space used for this automatic caching, and the latest-opened files will replace older ones when that disk space runs low. You can use Group Policy to specify many Offline Files options, including a list of filename extensions which may not be cached. Microsoft Access files are, for example, part of the default do-not-cache list since caching a database used by multiple users will usually result in issues when the cached copy is synchronized.

More Resources:

• Read KB article 884739 for yourself.
• Contact PSS to obtain the tool (this may cost you depending on your relationship with PSS).
• Learn more about configuring Offline Files here.
• Learn about Offline Files and security here.