Alles zum Thema Windows Clients für den Desktop: Windows 95 / 98 / NT / 2000 / XP / Vista / Win 7 — Q & A zu den Windows Client Versionen sowie Windows Media Center / Windows Home Server
Drive letters mapped in this way are not available during system startup for services nor do they persist across a reboot. However with a registry modification it is possible to assign a path to a drive letter during startup so it is available to system services and persists across a reboot.
Create a new registry entry "String Value" in the following key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\DOS Devices
The name should be "X:" where X is the drive letter.
The value should be the path in the form: \??\C:\some\directory
There are also tools available to make the necessary changes for you. See psubst for one such tool.