After installing and configuring Microsoft Credential Provider, info, warning
and error messages are being logged for successful logins.

Log Name:      Application
Source:        SymantecCredentialProvider
Date:          11/1/2016 11:19:54 AM
Event ID:      3
Task Category: (3)
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      Windows7x64.example.com
Description:
COPY OK in CSymantecCredential
_______________________________________________

Log Name:      Application
Source:        SymantecCredentialProvider
Date:          11/1/2016 11:19:54 AM
Event ID:      3
Task Category: (3)
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      Windows7x64.example.com
Description:
UnpackCredential succeeded
__________________________________________________

Log Name:      Application
Source:        SymantecCredentialProvider
Date:          11/1/2016 11:19:54 AM
Event ID:      3
Task Category: (3)
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      Windows7x64.example.com
Description:
setting _pkiulSetSerialization
 

Windows workstation with MCP for 2FA

These errors are expected, and working as designed. If Event Log Alerting & Reporting is enabled, the events can be filtered out.