Adobe Illustrator Operation Cannot — Complete Because Of An Unknown Error Parm !!link!!
: This is the most common solution. Hold Alt + Control + Shift (Windows) or Option + Command + Shift (macOS) while launching Illustrator to restore default settings. Note that this will remove your custom settings.
Adobe Illustrator's "The operation cannot complete because of an unknown error (PARM)" : This is the most common solution
Update or repair the application