MacOS – I suddenly cannot open any files in Script Editor.app

Today, I was working on an .scpt file in Script Editor.app, when, suddenly, Script Editor would not allow me to save the file. It was a seemingly random occurrence; I had not done something unique when the error surfaced. I had successfully saved this file in Script Editor dozens of times today.

I then Quit Script Editor and double-clicked on the .scpt file in Finder, to open the file in Script Editor (which is my default application for .scpt files).

Script Editor responded with the following error dialog:

It reads:

The document "My script.scpt" could not be opened.

I can launch Script Editor and I can create a New Document. But, I cannot open an existing document.

What I've tried:

• Restarting and shutting down the computer

• Running "First Aid' in Disk Utility.app

• Opening Script Editor.app via the right-click context menu in Finder

• Opening a .scpt file via the menu bar in Script Editor (File → Open...)

• Opening a .scpt file via the right-click context menu in Finder

• Creating a new document in Script Editor that contains zero characters. I can successfully save new documents in Script Editor, so I saved this .scpt file to my Desktop. But, after I closed the document window, I could not open the document in Script Editor.

• All of my .scpt files originated in (i.e., were created by) Script Editor.

• It may be important to note that I could open the .scpt files in TextWrangler.app and Atom.app.

Here is the Sharing & Permissions pane for the app file (via Get Info window in Finder):

These two questions are similar to my own:

• Can't save AppleScript file when created by touch

• Why am I getting “Error -1,752” when trying to save in Script Editor?

However, the solutions do not apply to my scenario.

Short of re-installing the OS, is there anything that I can do to get Script Editor up and running again?

_{OS X El Capitan, version 10.11.6.}

_{Script Editor Version 2.8.1 (183.1)}