Error msg when trying to save file

What have you done for all-purpose trouble-shooting so far? 
Resetting Preferences after making sure all customized presets like Actions, Patterns, Brushes etc. have been saved might be a good starting point:
https://helpx.adobe.com/photoshop/using/preferences.html
https://helpx.adobe.com/photoshop/kb/basic-trouble-shooting-steps.html