Error when trying to connect to SSAS db via Excel on Windows 7

Some colleagues of mine upgraded their host system to Windows 7. Since that moment they couldn’t connect to our test SSAS server to test the new developed analysis cubes from Excel.

The following error occured:

The following system error occurred: The security database on the server does not have a computer account for this workstation trust relationship. .

My collegue Bas Kroes found the answer while searching the internet on the MS forums:

Did you by chance install Windows 7 on your workstation (the one you re-imaged)?  I understand that this issue arises in Windows 7 due to a component called “Windows Live Sign In Assistant”.  From my understanding, you basically have 3 options:

1. Configure Kerberos on your SSAS server http://support.microsoft.com/kb/917409
2. Uninstall Windows Live Sign In Assistant on each workstation
3. Use SSPI=NTLM in your connection string to force NTLM as the Security Support Provider Interface

#1 is probably the preferred method, as it addresses the problem server-side, whereas #2 and #3 are both client-side workarounds.

found at http://social.msdn.microsoft.com/Forums/en-US/sqlanalysisservices/thread/b058635f-6d3e-4240-a555-1dbd945ae25a