post upgrade from 7.6.1.0 to 7.7.1.2 fails

Hi All,

               I have tried upgrading my instance to 7.7.1.2 and tried upgrading using the upgrade wizard.

The health check and all went well.

But during the post upgrade when it was about to complete it threw an error.

When i checked the php_error logs the below were there:Angel Magana Tevfik Tümer Shijin Krishna Ishani Lad

PHP Warning: file_put_contents(cache/upgrades/upgrade_state.php): failed to open stream: Invalid argument in C:\inetpub\wwwroot\<>\cache\upgrades\driver\UpgradeDriver.php on line 229
[17-Apr-2017 11:46:36 UTC] PHP Warning: file_put_contents(cache/upgrades/upgrade_state.php): failed to open stream: Invalid argument in C:\inetpub\wwwroot\<>\cache\upgrades\driver\UpgradeDriver.php on line 229
[17-Apr-2017 11:47:01 UTC] PHP Warning: file_put_contents(cache/upgrades/upgrade_state.php): failed to open stream: Invalid argument in C:\inetpub\wwwroot\<>\cache\upgrades\driver\UpgradeDriver.php on line 229
[17-Apr-2017 11:47:09 UTC] PHP Warning: file_put_contents(cache/upgrades/upgrade_state.php): failed to open stream: Invalid argument in C:\inetpub\wwwroot\<>\cache\upgrades\driver\UpgradeDriver.php on line 229
[17-Apr-2017 11:55:29 UTC] PHP Warning: require(custom/modules/Connectors/metadata/connectors.php): failed to open stream: No such file or directory in C:\inetpub\wwwroot\<>\include\connectors\utils\ConnectorUtils.php on line 256

When i exported the error log file in the upgrad wizard the last logs were like:"case insensitive file system enabled"

Can any one please brief about what went wrong here.I have been unable to upgrade the instance from a few days and am on fire.

I am on windows server.

Since the upgradation fails and i click on go to home page the system throws 500 error.And the followin are registered on the log.

 require(): Failed opening required 'custom/modules/Connectors/metadata/connectors.php' (include_path='C:/inetpub/wwwroot/<>;C:/inetpub/wwwroot/<>/vendor;.;C:\php\pear') in C:\inetpub\wwwroot\<>\include\connectors\utils\ConnectorUtils.php on line 256

Regards

Sidhu