Photoshop on mac "could not save [file] because write access was not granted" I've been seeing this error a lot lately:




  Could not save [file] because write access was not granted


I've checked all the standard reasons why permission to save a file might be denied:


The file is not open in any other application
The user does have access to the drive and directory
No other users on a network are accessing the file
The file is not read-only
No other save operations are happening
The connection to the drive is fine


I've seen this happen on Lion and Mavericks. I've only ever seen it on a Mac, and only ever with Photoshop, with .PSD files.
After some trial and error, I tracked it down to the file being selected in Finder. 

It seems like when Finder is displaying a preview of a PSD, it locks the file. 

It seems to only happen in this view mode:



Selecting another file in Finder, or switching view mode, or closing the finder window, all prevent this error.



So while Finder is like this, the file won't save:



Clicking off it frees it for saving:



As does switching to this view mode to one that doesn't show a preview: