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:

IMHO the problem is caused by the SMB protocol, then in fact there are some ”strange process” opened by the Finder. I changed the server protocol for AFP and everything works well. In my case I changed shared folder’s settings in Server app ver. 4.1.5, but this works is mac os x System Preferences as well. The eventual disadvantage – there is no connection of PCs to the server.