Network Letters
Letters configured in section [NetworkLetters] are not accepted being used for local drives.
They overrule letters configured in external INI files too.
Here you should enter drive letters used as network shares or as subst drives. This way the USBDLM service can consider them even they are not created yet, e.g. at boot or logon time. Furthermore drives which are created later, as TrueCrypt drives, should be configured here.
Up to V4.2 the name of this section was [ExcludedLetters], which still works for compatibility. It was renamed because many users configured the letters of their internal drives here which is wrong and dangerous:
Do not configure letters of local drives here, USBDLM might remount them because they are then "reserved" for network/subst/truecrypt use!
Alternative: Just configure enough drive letters in the DriveLetters sections.
In contrast to other config sections here are Letters1 to 26 read because some users reported that 9 letters are not enough.
Sample to exclude F and G:
[NetworkLetters]
Letter1=F
Letter2=G
Letter3=H
or short:
[NetworkLetters]
Letters=F,G,H
or using a range:
[NetworkLetters]
Letters=F-H
In this section only letters are allowed.
If you want to admin the settings from a central point, the USBDLM.INI can be read from a network share:
[Settings]
ServerINI=\\192.168.1.1\USBDLM_share\usbdlm.ini
For this USBDLM.INI only section [NetworkLetters] is read!
The file is read from the context 'LocalSystem' of the computer which the USBDLM service is running on with null network credentials. So the share should have read access granted to 'Everyone' and furthermore the share must be allowed to be a null session share:
http://www.uwe-sieber.de/nullsessionshares_e.html
For network drives only an UNC path works here because on system startup the network drive letters are no yet created and furthermore they exist in the context of the interactive user only under XP and higher.
To avoid delays it's read on startup of the USBDLM service only.
Letters1 to 26 can be used in addition.