Solution by Event Log Doctor

SChannel is a Windows SSP (Security Support Provider), similar to Kerberos and NTLM.

SChannel provides SSL/TLS communication through the SSPI (Security Support Provider Interface) for applications like Internet Explorer, IIS, SQL Management Studio and many more.

Schannel event logging can be controlled through the registry, and by default logs only "Errors" (http://support.microsoft.com/kb/260729).

On workstations, Schannel errors can usually be ignored.

Common error codes depicted in Schannel events are as follows:

TLS1_ALERT_CLOSE_NOTIFY (0)
TLS1_ALERT_UNEXPECTED_MESSAGE (10)
TLS1_ALERT_BAD_RECORD_MAC (20)
TLS1_ALERT_DECRYPTION_FAILED (21)
TLS1_ALERT_RECORD_OVERFLOW (22)
TLS1_ALERT_DECOMPRESSION_FAIL (30)
TLS1_ALERT_HANDSHAKE_FAILURE (40)
TLS1_ALERT_BAD_CERTIFICATE (42)
TLS1_ALERT_UNSUPPORTED_CERT (43)
TLS1_ALERT_CERTIFICATE_REVOKED (44)
TLS1_ALERT_CERTIFICATE_EXPIRED (45)
TLS1_ALERT_CERTIFICATE_UNKNOWN (46)
TLS1_ALERT_ILLEGAL_PARAMETER (47)
TLS1_ALERT_UNKNOWN_CA (48)
TLS1_ALERT_ACCESS_DENIED (49)
TLS1_ALERT_DECODE_ERROR (50)
TLS1_ALERT_DECRYPT_ERROR (51)
TLS1_ALERT_EXPORT_RESTRICTION (60)
TLS1_ALERT_PROTOCOL_VERSION (70)
TLS1_ALERT_INSUFFIENT_SECURITY (71)
TLS1_ALERT_INTERNAL_ERROR (80)
TLS1_ALERT_USER_CANCELED (90)
TLS1_ALERT_NO_RENEGOTIATION (100)
TLS1_ALERT_UNSUPPORTED_EXT (110)