I am getting the following error when browsing to localhost/umbraco after upgrading from 4.7.1 to 4.7.2

umbraco.DataLayer.SqlHelperException: Umbraco Exception (DataLayer): SQL helper exception in ExecuteNonQuery ---> System.Data.SqlClient.SqlException: Conversion failed when converting from a character string to uniqueidentifier.     at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)     at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)     at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)     at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)     at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, SqlDataReader ds)     at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean asyncWrite)     at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(TaskCompletionSource`1 completion, String methodName, Boolean sendToPipe, Int32 timeout, Boolean asyncWrite)     at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()     at Microsoft.ApplicationBlocks.Data.SqlHelper.ExecuteNonQuery(String connectionString, CommandType commandType, String commandText, SqlParameter[] commandParameters)     at umbraco.DataLayer.SqlHelper`1.ExecuteNonQuery(String commandText, IParameter[] parameters)     --- End of inner exception stack trace ---     at umbraco.DataLayer.SqlHelper`1.ExecuteNonQuery(String commandText, IParameter[] parameters)     at umbraco.BasePages.BasePage.ClearLogin()     at umbraco.BasePages.BasePage.OnLoad(EventArgs e)     at System.Web.UI.Control.LoadRecursive()     at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

Not sure how to fix this problem. What I did was, the suggestions listed here:

http://www.blix.co/blog/2014/6/5/follow-the-path-upgrading-umbraco-from-v4-to-v7.aspx

1. Download upgrade release
2. Copy /Config, /Install, /Umbraco, /Umbraco_client and /bin folders
3. Load the site and let Umbraco update the database where required.

Not sure where umbraco is supposed to update the database or if it has done so in the background, cause when I load up the site, the homepage and all pages of the site render fine, but the Umbraco Backoffice localhost/umbraco/ url is giving me a 500 ERROR and viewing the Umbraco Logs in the umbraco_logs table, gives me the Error message above.

How can I resolve this?