Troubleshooting Client Drive Mapping

This article will give you a vast idea about many common client drive mapping inquiries and issues along with their respective explanation or resolution.

Client Drive Mappings Do Not Create For Any User

  • If the ICA-tcp port properties are set to “Inherit User Config” make sure the Active Directory profile for the users having the issue have the “Connect client drives at logon” box checked. (Which is the default setting.)

  • Ensure the option to disable client drive mappings on the ICA-tcp listener in Terminal Services Configuration is not enabled. A Group Policy may gray out the check box selection.

  • Removable drives must be inserted / attached to the client computer before the ICA connection. After the removable drive is inserted / attached, ensure the client is not reconnecting to a disconnected session or that the drive is not being restricted by a policy.
  • For Windows 2000 and 2003 Terminal Server Installations, ensure the following registry entry exists and that the process, wfshell.exe, is running inside the session:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsNT\CurrentVersion\Winlogon
    Key Name: AppSetup
    Value: Cmstart.exe
    CTX983798 – What Does the CMSTART Command Do?
  • Ensure the Client Network Service is started. Do not attempt to restart the Client Network Service when there is an existing ICA connection to the server. If the Client Network Service does not appear within services, verify that the key, CdmSerivce, and its subcatergories, Enum and networkProvider, along with their values are present under:
    Check another working server for proper registry settings.
  • Ensure the RPC Service is started.
  • Ensure that Client Network is visible under Network Neighborhood. If it is not, follow the steps listed below:

a. Start Registry Editor (Regedt32.exe) and go to the following key:
The value for ProviderOrder contained only LanmanWorkstation.
Add CdmService, so that the Value now reads “CdmService,LanmanWorkstation.”

b. For Presentation Server 4.5, ensure the path defined under the CommonFilesDir value from HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion is correct.

c. Restart the server

  • Ensure Cdmprov.dll is in the \system32 directory.
  • Ensure Microsoft files Mpr.dll, the Multiple Provider Router dll, and Mup.sys (the Multiple UNC Provider driver) are present.
  • Does drive mapping fail for the administrator? If not, ensure users have sufficient rights to the dlls, exes, and registry settings outlined in this section.
  • Does the command chgcdm /default work?
  • Does the command net use * \\client\c$ work? If it does not, a System Error 67 appears.
  • Is a local Windows 2000/2003 policy “Strengthen default permissions of global system objects” disabled? If so, Enable this policy or apply Citrix Hotfix XE104W2K3R01 / MPSE300W2K3R03 or the Operating System equivalents. Citrix Presentation Server 4.0 includes the fix.
  • Check the event log for CDM error messages.
  • Can a similar function be performed in a Microsoft network scenario?
  • Verify that the Cdm.sys file is in the \Program Files\Citrix\System32\drivers directory.
  • For Terminal Server 4.0 installations, check to see if the following registry entry exists:
    Key Name: Userinit
    Value: Ctxlogon.exe
  • If using Web Interface, does the template.ica or default.ica file have a value of CDMAllowed=Off (for Presentation Server Client version 9.x or earlier) or CDMAllowed=False (for Presentation Server Client version 10.x or later)
  • CTX117481 – Manually Mapped Client Drives are not Mapped when Reconnecting to a Disconnected Session

Configuring Server Drive Letters For Client Drive Mapping

The Citrix XenApp plugin/ICA Client supports client drive mapping functionality. Client drive mapping allows users logged on to a XenApp server from a client device to access their local drives transparently from the ICA session. Client devices can transparently access files contained on the local machine and data can be cut and pasted between local and remote sessions using the clipboard. During the initial installation of XenApp, the administrator is prompted to modify the server drive letter assignments to avoid conflicts with user drive letters (except with Windows Server 2008 where drive remapping is not supported).

CTX457309 – MetaFrame/Presentation Server Drive Remapping Best Practices

The default drive letters assigned to client drives start with V and work backwards assigning a drive letter to each fixed disk and CD ROM. (Floppy drives are assigned their existing drive letters.) This method yields the following drive mappings:

Client drive letter Is accessed by the Citrix server as

If the Citrix server drive letters do not conflict with client drive letters, the client drive letters can be accessed with their existing drive letters. So that the Citrix server drive letters do not conflict with the client drive letters, you need to change the server drive letters to higher drive letters. For example, changing Citrix server drives C to M and D to N allows client devices to access their C and D drives directly.

How to Map Client Workstation Network Drives in an ICA Session

Use the Net Use command in a logon script to map client network drives, even when the Citrix Management Console policy is enabled. For design and performance reasons, if the client mapped network drive is accessible on the network from the Citrix server, Citrix prefers that you do not following the solution below and that the network drive be mapped in a regular Windows NT logon script.

The below point items are valid for all versions of XenApp.

  • During logon, the ICA Client informs the server of the available client drives, COM ports, and LPT ports.
  • Client drive mapping allows drive letters on the Citrix server to be redirected to drives that exist on the client device; for example, drive H in a ICA user session can be mapped to drive C of the local computer running the Citrix ICA Client. These mappings can be used by the File Manager or Explorer and your applications just like any other network mappings. Client drive mapping is transparently built into the standard Citrix device redirection facilities. The clients disk drives are displayed as share points to which a drive letter can be attached. The Citrix server can be configured during installation to automatically map client drives to a given set of drive letters. The default installation mapping maps drive letters assigned to client drives starting with V and works backwards, assigning a drive letter to each fixed disk and CD-ROM. (Floppy drives are assigned their existing drive letters.)
  • You can use the net use and change client commands to map client devices not automatically mapped at logon.
    Here is the command and syntax:
    net use y: \\client\c$
    where y is the drive letter in a session and c is the client drive letter you want to map.

Presentation Server 4.0 with Hotfix Rollup Pack 1 automatically maps Network Drives. [From PSE400W2K3R02][#127532]: “Network drives for client devices incorrectly map automatically as local client drives.”

How to Disable Specific Client Drive Mappings such as the A: drive

Perform the following steps:

  • Open the Module.ini file in a text editor (for example, Notepad) on the client device. In most cases, this file is in the \Program files\Citrix\ICA client directory.
  • Add the following entry to the end of the [ClientDrive] section:
    DisableDrives =A,D,F
  • Save the changes and exit the text editor.
  • Restart the ICA Client and establish a connection to the Citrix server.

This entry prevents the client side drive letters A, D, and F from being mapped. The entry is not case-sensitive. If someone attempts to map a “disabled drive” through the client network within an ICA session (that is, net use * \\client\D$), the following error message appears: “System Error 55 has occurred. The specified network resource is no longer available.”

The same restriction can be applied to an .ica file (used with published applications) by adding “DisableDrives=” in the [Wfclient] section. Again, use a text editor to make this change.

Another solution is to enable a policy through the management console.

How to Map Only One Client Drive at Logon

  • From Terminal Services Configuration, double-click your connection type.
  • Select Client Settings.
  • Clear Inherit user config.
  • Clear Connect Client drives at Logon.
  • Click OK.
    : Do not select Disable Client Drive Mapping; this will disable all future client drive mappings.
  • Create a logon script (.bat file) in the following format:
    net use y: \\client\c$
    where y is the drive in a session and c is the client drive you want to map.
    : This does not permanently disable clients from mapping another drive when they are logged on.

How to Map Client Drives in Ascending Order

By default, when server drives are not remapped (C and D) or the above initialclientdrive registry value is set, client drives are mapped in descending order. See “Configuring Citrix Server Drive Letters for Client Drive Mapping” for more information. The methodology explained in “How to Map Only One Client Drive at Logon” can be used to create the mapping in ascending order.

How to Make the Server Drives Appear as a Client Drive When Using the PassThrough Client

From the 6.20.986 ICA Win32 Client ReadMe:

Client drive mapping on the pass-through client was restricted to the drives on the client device. The client could not map local or network drives configured on the MetaFrame server in a pass-through session.

Local or network drives configured on the MetaFrame server can now be mapped by the pass-through client.

For version 9.xx, open the Module.ini file in a text editor and add the following line to the [ClientDrive] section of the file: NativeDriveMapping=TRUE

For version 10.xx

  • Run Regedit.
  • Navigate to:
    HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\ICA Client\Engine\Configuration\Advanced\Modules\ClientDrive
  • Create the Reg Value: NativeDriveMapping
    Reg Type: REG_SZ
    Add the Value: True
  • When this flag is set, the client drives on the client device are not mapped and are not available. The drives configured on the MetaFrame server are mapped and are available to the pass-through client.
    CTX126763 – Client Drive is Not Mapped Using ICA Client Version 12 as Pass-Through Client

@echo off
rem *
rem * Wait on redirector to connect client drive.
rem * In this case, we are using the V: drive as the client C:.
rem * We also need something to look for on the client drive.
rem * Adjust the settings accordingly.
rem * echo Connecting…
DIR %homedrive% /w > V:\tag.txt
IF EXIST V:\tag.txt GOTO :Connected
goto :Delay :Connected
DEL V:\tag.txt
START /NORMAL /WAIT Explorer.exe

Files saved to a client drive is successful but the file is corrupt or the saved file reports an invalid memory location.

If the client drive or disk does not have enough space, the file copy passes but the file is truncated or the file will not copy and gives an invalid memory location error.

Client Drives content may disappear in Windows Explorer and at a command prompt when applications open more than 20 file handles

Add the bolded entry to the Module.ini [ClientDrive] section. The Module.ini is in the \Program Files\Citrix\ICA Client directory.

MaxOpenContext = (A number ranging from 21 to 1024.)


DriverName = VDCDM30.DLL
DriverNameWin16 = VDCDM30W.DLL
DriverNameWin32 = VDCDM30N.DLL
MaxWindowSize = 6276
MaxRequestSize = 1046
CacheTimeout = 600
CacheTimeoutHigh = 0
CacheTransferSize = 0
CacheDisable = FALSE
CacheWriteAllocateDisable = FALSE
= 50
DisableDrives =

: The default is 20 file handles per drive. If it becomes necessary to increase this number, it is possible there is a handle leak with the applications accessing the client drives.

Cannot Save Word97 Docs with Long Filenames to Citrix Drive A:

When the File Open or Save As dialog box is opened, Word brings up the last drive letter used. If that drive was a remote share, Word starts a search for the correct remote share at drives C through Z, because drive letters A or B are not usually referenced as network shares. If Word cannot find the correct remote share, it makes a new connection with a NULL local drive name.

Saving Long Filenames with the DOS Client

The standard 8.3 format must be used in saving to local drives with the ICA DOS Client. The Citrix server does not physically write the file, rather, the ICA DOS client is sent the file and the ICA Client writes it. Thus, the ICA Client cannot write a long filename because the DOS operating system does not support long filenames.

Internet Explorer 5.0 saves HTML pages with all images by creating its own directories and file names. These file names are long file names that are not compatible with the DOS Client.


About Murugan B Iyyappan

Working as a Consultant - Citrix solutions architect with 18 years of experience in the IT industry. Expertise in Citrix products and Windows platform.
This entry was posted in Citrix XenApp, Citrix XenDesktop and tagged . Bookmark the permalink.

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