SharePoint central admin site is not opening, getting an error, Sorry something went wrong

SharePoint central admin site is not opening, getting an error, Sorry something went wrong

Solutions:

Method 'Upgrade' in type 'Microsoft.SharePoint.WorkflowServices.WorkflowServiceApplicationProxy' message

Solution :

There's an update that assumes you already have SP1 deployed - if you go back to Central Admin you'll note the UI changes for O365 & Yammer are now showing up. The fix is to deploy one more hotfix to your server - you can download it from here: http://www.microsoft.com/en-us/download/details.aspx?id=42898 

No reboot required - install the update, open up that PS window & you're blissfully error free.