Oneif you have recently changed the ownership of workflows, they might still be referencing their old owners.
We recently had a situation where we changed ownership of a workflow and disabled the old owner, everything looked fine until the workflow was triggered. it failed with an error message having to do with user rights and privileges
How did we resolve the issue? well we found that all you have to do is deactivate the workflow and reactivate it gain, that seemed to clear any references to the old owner and the error messages went away.
if you find that you all the tiles at the top of the screen are suddenly now showing again click on the button below (see image below), the tiles will suddenly appear.
This is quite a simple one but caused some confusion as we initially thought the page was not loading correctly.