Mastering Windows Explorer (part 2) - What's What and Where in a User Profile

2. What's What and Where in a User Profile

A user profile contains all the settings and files for a user's work environment. In addition to personal documents and media files, this profile includes the user's own registry settings, cookies, Internet Explorer Favorites, and user data and settings for installed programs.

By default, each user who logs on to a computer has a local user profile, which is created when the user logs on for the first time. Local user profiles are stored in %SystemDrive%\ Users. Each user's profile is stored in a subfolder where the user account name is the folder name (for example, C:\Users\Katy). The entire path for the current user's profile is accessible via another commonly used environment variable, %UserProfile%.

To open your user profile, click Start and then click your user name at the top of the right column. Using the default Windows Explorer view settings, what you see will look much like Figure 5. For a new user profile, Windows creates 11 subfolders, each intended to hold a different category of personal information.

In addition to these visible document folders, a user profile includes a number of hidden registry files, a hidden AppData folder, and several junctions provided for compatibility with Windows XP. In the remainder of this section, we break out some of the more interesting folders and subfolders within this location.

2.1. Default User Data Folders

The 11 visible data folders are as follows:

• Contacts This folder first appeared in Windows Vista and was designed to store contact information used by Windows Mail. It is not used by any programs included in Windows 7 and is maintained for compatibility purposes with third-party personal information management programs.

• Desktop This folder contains items that appear on the user's desktop, including files and shortcuts. (A Public counterpart also contributes items to the desktop.) A link to this location appears by default in the Favorites section of the navigation pane.

• Downloads This folder, which was introduced in Windows Vista and has no predecessor in Windows XP, is the default location for storing items downloaded from websites. A link to this location appears by default in the Favorites section of the navigation pane.

• Favorites This folder contains Internet Explorer favorites. To open it quickly in Windows Explorer, use the shortcut shell:favorites.

• Links This folder contains shortcuts that appear under the Favorites heading in the navigation pane. You can create shortcuts here directly, but it's easier to drag items from a file list or the address bar directly into the navigation pane.

• My Documents This folder is the default location for storing user documents in most applications.

• My Music This folder is the default location for ripped CD tracks. Most third-party music programs store downloaded tracks in a subfolder here.

• My pictures This folder is the default storage location for programs that transfer images from external devices (such as digital cameras).

• My Videos This folder is the default location for programs that transfer video data from external devices.

• Saved Games This folder is the default storage location for game programs that can save a game in progress. All games included in the Windows 7 Games Explorer use this folder.

• Searches This folder stores saved search specifications, allowing you to reuse previous searches.

2.2. Application Data

The hidden AppData folder, introduced in Windows Vista, is used extensively by programs as a way to store user data and settings in a place where they'll be protected from accidental change or deletion. This folder (which performs the same function as the Application Data folder in Windows XP) contains application-specific data—customized dictionaries and templates for a word processor, junk sender lists for an e-mail client, custom toolbar settings, and so on. It's organized into three subfolders, named Local, LocalLow, and Roaming. The Roaming folder (which is also accessible via the environment variable %AppData%) is for data that is made available to a roaming profile (a profile stored on a network server; the server makes the profile available to any network computer where the user logs on). The Local folder (which is also accessible via the system variable %LocalAppData%) is for data that should not roam. The LocalLow folder is used only for Internet Explorer Protected Mode data.

Subfolders under AppData\Local include the following:

• Microsoft\Windows\History This hidden folder contains the user's Internet Explorer browsing history. You can open it directly using the shortcut shell:history.

• Temp This folder contains temporary files created by applications. The %Temp% variable points to AppData\Local\Temp.

• Microsoft\Windows\temporary Internet Files This hidden folder contains the offline cache for Internet Explorer as well as attachments saved from Microsoft Outlook messages. Use shell:cache to open it in Windows Explorer.

Subfolders under AppData\Roaming\Microsoft\Windows include the following:

• Cookies This hidden folder contains Internet Explorer cookies and can be accessed directly using the shortcut shell:cookies.

• Libraries You'll find XML files that define the contents of default and custom libraries here.

• Network Shortcuts This folder contains shortcuts to network shares that appear in the Computer folder. The folder is not hidden; you can add your own shortcuts here, although it is easier to right-click in Computer and choose Add A Network Location.

• Recent Items Shortcuts to recently used documents are automatically saved here; if you customize the Start menu to include a Recent Items link, the most recent 15 shortcuts appear on that list.

• SendTo This folder contains shortcuts to the folders and applications that appear on the Send To submenu. Send To is a command that appears on the shortcut menu when you right-click a file or folder in Windows Explorer (or on the desktop). The SendTo folder is not hidden. You can add your own items to the SendTo menu by creating shortcuts here. Use shell:sendto to open this folder and add or delete shortcuts.

• Start Menu This folder contains items that appear on the Start menu. (The Start menu also includes items stored in a Public counterpart to this folder, %ProgramData%\Microsoft\Windows\Start Menu\Programs\Startup.)

• Templates This folder contains shortcuts to document templates. These templates are typically used by the New command in Windows Explorer (on the shortcut menu) and are referenced by the FileName value in the HKCR\class\ShellNew key, where class refers to the extension and file type.

2.3. Junctions Used for Compatibility with Windows XP

Most applications that write to locations within the user profile query the operating system as needed, rather than writing to absolute addresses. A well-behaved program that was originally written for Windows XP will thus have no trouble accommodating the changed names and locations of profile folders in Windows Vista and Windows 7. On the other hand, a program that looks for Documents And Settings (the root of profile folders in Windows XP) as an absolute address could encounter problems when it tries to open or save files.

The solution? Beginning with Windows Vista, each user profile contains junctions (reparse points) that redirect Windows XP folder names to the appropriate names as used in Windows Vista and Windows 7.

You can see how these junctions are set up by running a Command Prompt session and typing cd %userprofile% and then dir /ads (the /ads switch restricts output to directories that also have the system attribute). The output from this command will look something like Figure 6.

The reparse points in this directory list are identified by the label <JUNCTION>. The fourth column in the display lists the Windows XP folder name (SendTo, for example) followed, in brackets, by the redirect address (C:\Users\edbott\AppData\Roaming\Microsoft\Windows\ SendTo). If you display the same folder (%UserProfile%) in Windows Explorer, with hidden and system files visible, the junctions will look like shortcuts and won't include any information about their targets.

Table 1 lists the junction points created by default in the Users folder.

2.4. The VirtualStore Folder

Many legacy applications write data (such as configuration information) to areas that are ordinarily inaccessible to standard accounts. This behavior presented few problems in Windows XP because most users ran with administrative privileges. In Windows 7 (as in Windows Vista), the User Account Control (UAC) feature means that all users, even those with administrator accounts, run with a standard user token in ordinary operation. To prevent compatibility problems, UAC redirects problematic file and registry writes (and subsequent reads) to per-user virtualized locations.

Note:

If you disable UAC, file and registry virtualization are disabled as well. If you log on using an account in the Administrators group with UAC disabled, any program you run can write directly to locations in the file system and the registry that would otherwise be protected by UAC.

So, for example, if an application, running in your security context, attempts to write to a location within %ProgramFiles%, the write will be redirected to a comparable location within %LocalAppData%\VirtualStore. When the application subsequently reads what it has written, the read request is redirected to the same virtualized location. As far as the application is concerned, everything is perfectly normal, and the operating system has prevented standard-user access to the %ProgramFiles% folder.

If you open a folder in which a virtualized write has occurred, a Compatibility Files link will appear on the Windows Explorer toolbar, as in this example from a program that insisted on writing a configuration file to the Windows folder:

Clicking Compatibility Files will take you to the VirtualStore location where the data is actually written.

A similar form of virtualization protects sensitive areas of the registry. Programmatic access to HKLM\Software is redirected to HKLM\Software\Classes\VirtualStore.

Note the following about virtualization:

• Virtualization does not affect administrative access to files or registry keys.

• Virtualization does not affect 64-bit processes.

• Virtualized data does not move with roaming profiles.

• Virtualization is provided for the sake of compatibility with current legacy programs; Microsoft does not promise to include it with future versions of Windows.

3. Common Profiles

Windows creates a local user profile for each user account, storing the profiles in subfolders of %SystemDrive%\Users with folder names that match the account names. In addition to these user profiles, the operating system creates two others:

• public The Public profile contains a group of folders that mirror those in your user profile. You can see the Public Documents, Public Music, Public Pictures, and Public Videos folders in their matching libraries. The advantage of these folders is that other users can save files to these locations from different user accounts on the same computer or from across the network. The Windows XP equivalent of the Public profile is called All Users, and this profile also serves to store application data designed to be available to all users. In Windows 7 and Windows Vista, this "all users" application data is stored in %SystemDrive%\ProgramData (which has its own system variable, %ProgramData%).

• Default When a user logs on to a computer for the first time (and her account is not set up to use a roaming profile or mandatory profile), Windows creates a new local profile by copying the contents of the Default profile to a new folder and giving it the user's name. Therefore, you can configure the Default profile the way you want new users' initial view of Windows to appear. Note that the Default folder is hidden, and you must approve a UAC consent dialog box to add files to it.

If you enable the Guest account, it gets its own profile in the Users folder as well.

Warning:

In the unlikely event that Windows is unable to access your user profile when you log on, the system might create a temporary user profile in %SystemDrive%\Users\Temp, I warning you at logon that it has done so. Any changes you make to this temporary profile (including any files you save in its data folders) will be deleted when you log off.