'The computer must be trusted for delegation and the current user account must...' error when trying to connect to sql server 2008
According to KB3000850, this affects domain-joined Windows 8.1 computers after installing security update 2992611 or update 3000850.

I added the following value under:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Cryptography\Protect\Providers\df9d8cd0-1501-11d1-8c7a-00c04fc297eb

ProtectionPolicy = 1 (DWORD)

Now I can connect.

I found some other postings about this:

https://blog.sqlauthority.com/2017/04/01/sql-server-system-security-cryptography-cryptographicexception-error-generating-xml-document/

https://social.technet.microsoft.com/Forums/windows/en-US/47faab6b-d717-4068-bee4-c694811e0066/credential-manager-problems-error-0x80090345?forum=w8itpronetworking