I created my profile after changing:

HKEY_LOCAL_MACHINE/Software/Microsoft/Windows NT/CurrentVersion/ProfileList/ProfilesDirectory
to "D:\"
therefore my profile is now D:\username.

while everything else works as expected, all metro apps crash immediately after starting (I click, animation: colored fullscreen with logo in the middle, and back to the tile screen again).

I can replicate this every time with contacts, mail, weather, messages, etc.
changing profilesdirectory back to C:\users, removing my profile folder (via extended system settings, not removing the account itself), fixes the problem, but I need my stuff on D:, for small-SSD-reasons.

any ideas?

eventlogs, all apps have the same error. I can't find "Microsoft-Windows-TWinUI/Operational log" though...

Log Name:      Application
Source:        Microsoft-Windows-Immersive-Shell
Date:          18.08.2012 00:53:24
Event ID:      5973
Task Category: (5973)
Level:         Error
User:          desktop\Veit
Computer:      desktop
Activation of app Microsoft.BingWeather_8wekyb3d8bbwe!App failed with error: The remote procedure call failed. See the Microsoft-Windows-TWinUI/Operational log for additional information.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
    <Provider Name="Microsoft-Windows-Immersive-Shell" Guid="{315A8872-923E-4EA2-9889-33CD4754BF64}" />
    <TimeCreated SystemTime="2012-08-17T22:53:24.554571000Z" />
    <Correlation />
    <Execution ProcessID="3628" ThreadID="6900" />
    <Security UserID="S-1-5-21-3539164688-1331221575-805218810-1001" />
    <Data Name="AppId">Microsoft.BingWeather_8wekyb3d8bbwe!App</Data>
    <Data Name="ErrorCode">-2147023170</Data>