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Using Offline Files

by Mitch Tulloch, Chris Sanders

In the previous two articles titled Implementing Mandatory Roaming Profiles and How to Deploy Software Using Group Policy, we examined features of Microsoft IntelliMirror technologies that help make the job of administering a network of Windows desktop computers quick and easy in enterprise environments. In this third article of the series, Chris Sanders, a network administrator for one of the largest public school systems in Kentucky, explains how to implement Offline Files so that mobile users can access their data when they are away from the network.

"As if it weren't enough for your fellow employees to work their tails off while in the office, management has just given you the task of developing a system where you and other mobile users can work on their personal files when disconnected from the local network. Fortunately for us, Microsoft provides yet another Intellimirror technology in the form of offline files that will help you accomplish your goal. Here we will take a look at how to set this up.

"Offline files allow us to synchronize files between a shared network location and an individual computer. Using this strategy, every time you log off when connected to the network, the files set for synchronization will download from the network to your computer. Likewise, when you connect to the network after being disconnected, your computer will synchronize the files that have been changed with the files stored on the network.

Enabling Offline Files

"Before you can begin making any data available for offline use, you must first ensure that the offline files feature is enabled on the mobile systems connecting to the network as well as the server the files to be marked for offline use reside on. This is done by first double-clicking on the "My Computer" icon on your desktop. Click "Tools" on the windows drop-down menu and select "Folder Options." You can then point to the "Offline Files" tab and place a checkmark next to the "Enable Offline Files" option (Figure 1). Accept the changes by clicking the "OK" button to complete the process.

Figure 1
Figure 1: Enabling offline files on the server and client

"In this dialog you also have several configurable options to custom-tailor this feature to your particular needs. You can configure the time synchronization occurs, the frequency of synchronization reminders, the display of an offline files shortcut on the desktop, and the use of encryption on offline files. You may also configure the amount of disk space to be used for temporary offline files, and gain the ability to view and delete those files.

"One of the most useful options under the offline files dialog is found under the Advanced button. Here you can specify an action for your computer to take should it lose a network connection to the computer where the offline files reside (Figure 2). Once you select the remote computer the offline files are located on, you have two options. You can force your computer to be notified of the loss of connectivity and switch into a working offline state, or force your computer to continue as it was and not go into an offline state. The first option is more practical for long-term loss of connectivity, whereas the latter is best for when the loss of connectivity is expected to be very brief, such as a server reboot.

Figure 2
Figure 2: Specifying an action for your computer to take should there be a loss of connectivity

Making Files Available for Offline Use

"Having enabled offline files, you must now configure the appropriate files on your file server to be made available for offline usage. This requires that the files be located within a shared folder. Assuming all of the files you want available for offline usage are in one folder, you can share that folder by right-clicking it, going to properties, clicking the "Sharing" tab, and clicking the "Share this folder" radio button. You will then, of course, want to set the appropriate file access permissions for these files. If you are making users' individual files available to them for offline usage, then the chances are that they are already sitting on a file server inside of a shared folder. All that remains is to right-click the volume, folder, or file, and click the "Make Available Offline" option (Figure 3).

Figure 3
Figure 3: Making a folder available for offline access

A Quick Q & A

"That is all that is really involved in setting up offline files. However, there are a few more questions that you may run into after you get things up and going.

Q: "I have changed my account name and Offline Files no longer works--what's the deal?"

A: "This is very common. In order to fix it, you will need to regenerate the security identifier (SID) associated with your account. This can be done by using the csccmd command-line program from the Windows Resource Kit and using the command csccmd /resid."

Q: "Whenever my files synchronize, my processor utilization jumps to anywhere from 50% to 100%--do I have something misconfigured?"

A: "The Offline Files feature is doing exactly what it's supposed to in this case. The mobsync.exe service is what handles the synchronization process. It's tasked with examining all of the offline files and looking for changes in them as fast as possible. This being the case, it is going to use every bit of processing power available to it to get the task done ASAP."

Q: "Can I prevent certain files from being cached?"

A: "This is easily possible through the use of group policy. If you look under Computer Configuration > Administrative Templates > Network > Offline Files there should be an option called "Files not cached." You can configure this to exclude any files you do not want cached. This is a really good idea to prevent synchronization of extremely large files that may greatly delay the logon/logoff process."

Q: "Can I force a synchronization to happen without logging on or logging off?"

A: "Of course you can! This is done by using the Windows synchronization tool by going to the start menu, going to programs, then accessories, and clicking "Synchronize."

Q: "So, now that I have taken away any excuse my fellow employees have for not having to work at home, after hours, or when sick, how am I supposed to make new friends?"

A: "..."

Additional Resources

Here are some additional resources you may want to review before implementing Group Policy software installation in your own networking environment:

Mitch Tulloch is the author of Windows 2000 Administration in a Nutshell, Windows Server 2003 in a Nutshell, and Windows Server Hacks.

Chris Sanders is the network administrator for one of the largest public school systems in the state of Kentucky. For more about Chris, you can view his personal blog at

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