On Windows, when opening PREFERENCES / SETTINGS - SYNTAX SPECIFIC Sublime Text Build 3117 always creates an empty new default template for the syntax.sublime-settings file, even when there is an existing file. The file path in the tab appears to be correct, however upon attempting to save the file the following error appears:
“Unable to save D:\Users_username_\Dropbox\Documents\C:\Users_username_\AppData\Roaming\Sublime Text 3\Packages\User\Plain text.sublime-settings
Error: The filename, directory name, or volume label syntax is incorrect.”
Note the concatenation of the two file paths. The first path seems to be the path to the current project. The second path is the correct path to the syntax settings file.
Selecting SAVE AS and manually navigating to the save path functions as expected. The fact that a blank file is initially created, however, creates the danger of saving over existing settings.