Open (you can find it via Spotlight search with Cmd + Space ). Find any Adobe-related processes in the list.
If the 501 error is caused by network instability or the Creative Cloud Desktop App refusing to cooperate, bypass the App entirely. adobe error code 501
The most direct solution is to close the conflicting background processes: Open Process Manager Ctrl + Shift + Esc Command + Space Activity Monitor End Adobe-related tasks : Find and terminate any processes named Creative Cloud Open (you can find it via Spotlight search
Adobe’s installers are massive. If the connection hiccups for a fraction of a second during the handshake phase, the installer may try to "resume" a file that is now considered corrupt. The checksum fails, and the error code appears. and the error code appears.