SharePoint 2010 configuration wizard error ‘Method not found: ‘GetWYukonSafeConnectionString”

After installing Microsoft patches on SP2010, Central Admin was not accessible . When we tried to browse to CA, HTTP Error 503 came up.

I checked IIS, the Central Admin Application Pool had been stopped.

I reset IIS, It was started. But still CA not working.

Then I ran SharePoint 2010 configuration wizard and received the below error:

Error Message: Method not found: 'System.String Microsoft.SharePoint.Administration.SPSqlConnectionString.GetWYukonSafeConnectionStrin

It was because after upgrading SP2007 to SP2010, Microsoft Office SharePoint Server 2007 remained installed.

Solution:

1. In Control Panel >Uninstall Program > Uninstall Microsoft Office SharePoint Server 2007
2. Restart the server.
3. Run SharePoint 2010 configuration wizard

It was successful and the SharePoint 2010 Central Admin started to work.