Workaround gefunden:
Nach etwas Recherche habe ich bei Lenovo folgendes gefunden: Problem bekannt, bei neueren T-Modellen gibt es im Bios die Option, den sog. Legacy Support auszuknipsen. Serielle und parallele Schnittstelle werden damit deaktiviert. Dann funktioniert sowohl das Abziehen der Stromversorgung als auch das Abdocken ohne Probleme.
Was ich mich allerdings frage: warum man eine Docking Station baut, bei der man einige Schnittstellen nicht benutzen kann...
mozzihh
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Hier der Support-Eintrag:
http://www-307.ibm.com/pc/support/site.wss/MIGR-67382.html
Systems attached to ThinkPad Advanced Mini Dock or ThinkPad Advanced Dock may experience lock-ups or application hangs after losing AC Power -
ThinkPad R60, R61, R61i, T60, T60p, T61, T61p
Symptom
System that is attached to the ThinkPad Advanced Dock or ThinkPad Advanced Mini-Dock may hang or lock up if you lose AC power from the dock.
Affected configurations
Any of the following Lenovo systems attached to the ThinkPad Advanced Mini Dock (models 2504-10x) or ThinkPad Advanced Dock (models 2503-10x):
* ThinkPad R60
* ThinkPad R61, R61i
* ThinkPad T60, T60p
* ThinkPad T61, T61p
Solution
The ThinkPad Advanced Mini Dock or ThinkPad Advanced Dock needs continuous AC power to function. Legacy components (including serial or parallel peripheral devices in the dock) may cause unreliable operating system behavior if those devices lose power.
To ensure proper behavior by the ThinkPad Advanced Dock or ThinkPad Advanced Mini-dock, Lenovo recommends keeping a continuous supply of AC power attached to the back of the ThinkPad Advanced Dock and ThinkPad Advanced Mini-Dock.
Note: A new feature is added to newer versions of the system BIOS that will allow you to disable legacy devices. (Config>>Docking Station>>Legacy Devices on Mini-Dock>>Disabled)
This setting will prevent the ThinkPad from hanging when you lose AC power, but it will disable serial/parallel devices that are connected to the dock.