Published: 2021-12-31 | Last edited: 2022-01-10

Johnny Castaway screensaver for macOS


Tested in Monterey on M1 Max MBP and Big Sur on Intel i7 MBP.
Based on the zip provided by ztjuh:
I installed SoundBlaster drivers for audio, otherwise all Windows files are untouched.


The first time you run the app, a Settings file will be created and opened in a text editor:
~/Library/Application Support/JohnnyCastaway/JohnnyCastawaySettings.txt
Edit this file to your liking, save and close. Then run the app again to start the daemon.
You can later edit the Settings file by choosing 'Config' in the notification.
To apply changes made to the Settings file, just run the app again. This will restart the daemon.

To start the daemon, double-click the app. It opens in background, and a notification is shown.

To enable daemon at login, add to 'Login Items' in the 'Users & Groups' System Preferences pane.

To stop the daemon, run the app and choose the option 'Disable' in the notification.
Alternatively, manually run the following line in a terminal to kill the daemon:
kill -9 "$(ps -e | grep "[j]" | head -n 1 | xargs | cut -d' ' -f1)"


If the screensaver won't start, try:
1) Setting the RESOLUTION value to "original"
2) Lowering the CANCEL_WINDOW value

If you messed up the settings, move this folder to the trash (and run app again):
~/Library/Application Support/JohnnyCastaway/

If you get a bunch of Windows errors when exiting the screensaver, make sure you're running it from a writable disk, i.e. not directly from the mounted disk image

If Windows freezes and you seem stuck, [cmd-q] is your way out

If no notification is shown when you run the app, make sure you've allowed them in
System Preferences -> Notifications & Focus

If macOS complains the app "cannot be opened because the developer cannot be verified" or similar, right-click the app, then choose 'open' and 'open'

If macOS complains the app "is damaged and can’t be opened. You should move it to the Trash.", remove the quarantine xattr by running the following in a terminal:
sudo xattr -r -d /path/to/

Download: JohnnyCastawayMac-1.01.dmg [21MB]


- (This app)
- (Windows variant)
- (Used for running Win 3.11)
- (Used for notifications)
- (Used for dimming screen)
- (Solution for quitting DOSBox before sleep)

Release Notes

1.01 - 2022-01-10 - Made notifications clearer
- Added setting for notification duration
- Moved all Windows files to a separate dir (inside app package)
- Added function that quits DOSBox just before the computer goes to sleep, preventing trying but apparently failing to prevent login resolution bug.
- Added function that quits DOSBox if user moves the mouse while Windows is booting
- Small improvements here and there
- Bug fixes:
-- Don't try to execute DOSBox if a session is already running
-- Only kill daemon processes that are actually running, i.e. not script open in a text editor

1.0b 2021-12-30 - First release

By johsoderi - January 2022

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