The Vault 4.1.4 installer does not write the sgvaultuser encryption information to the proper registry key in 64-bit systems.Could not load connect string. There is probably an error with the encrypted password for the sgvaultuser database user. Contact technical support at http://support.sourcegear.com
The workaround would be to use Windows authentication for SQL Server, or modify the registry.
Here are the steps to modify the registry:
Using the info in CryptoKey and CryptoInitVector keys and their values from HKEY_LOCAL_MACHINE\SOFTWARE\SourceGear\Vault Server, manually create the same CryptoKey and CryptoInitVector keys and copy and paste the values to
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\SourceGear\Vault Server 64-bit
Leave the CryptoKey and CryptoInitVector keys in HKEY_LOCAL_MACHINE\SOFTWARE\SourceGear\Vault Server
Rename HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\SourceGear\Vault Server 64-bit to
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\SourceGear\Vault Server (delete the "64-bit")
Restart IIS and your web browser. You should now be able to log in.
This bug has been fixed in Vault 5.0