GUI64 brings a Windows-style desktop to the Commodore 64
GUI64 – GUI for the Commodore 64 running on top of the built-in ROM

GUI64 is a graphical layer for the Commodore 64 that runs on top of the built-in KERNAL ROM, offering a windowed file manager for floppy disks and SD2IEC devices. First released in November 2024, it now comes in Windows-like and Mac-like variants, with a taskbar, movable windows, and support for the Ultimate 64 and WiC64. Despite the name, it operates in text mode, aligning windows to an 8×8 character grid.
Strictly speaking, GUI64 should therefore be considered not a GUI, but a TUI (Text User Interface).
- snvzz
Too bad it's not open source.
("NC" creative commons)
- ButlerianJihad
Limitations:
GUI64 does not use the VIC-II’s bitmap graphics mode, but operates in text mode. GUI64 is therefore character set–based... Strictly speaking, GUI64 should therefore be considered not a GUI, but a TUI (Text User Interface).
Currently, there are no applications for GUI64.
So, it is a file manager, inferior to an orthodox file manager. It supports the mouse, and it can launch BASIC. If you like your KERNAL ROM, you can keep your KERNAL ROM.
I never ran GEOS. I saw it advertised, and it seemed fascinating, but perhaps "too early". I had become fluent in BASIC and proficient at the command line. I could decipher the DOS commands and device IDs. For me, time spent on the Commodore 64 was programming, or in a game or application, rather than pushing files/objects around on the desktop.
- Grimeton
One word: GEOS