First, I'm running MacOS X 10.11.6 on a MacBook Pro (17-inch, Mid 2009). Problem showed up today. I create a new blank document in TextEdit. I write what I need into the doc, then press ⌘+S to Save. I name the file with (in this example) "test save.rtf" When I click the <save> button, I get this error message: (I've attached a screenshot) The file "Untitled 8.rtf" couldn't be opened [OK] I have never seen this error before. It's saying "couldn't be opened" at point of save?