why there's some instruments that show me "error, this instrument can not be uploaded" ?
i have already installed Kontakt and reaktor 🤷♂️
There is no such error... If you mean "could not be loaded", then this might help
https://support.native-instruments.com/hc/en-us/articles/360000587769-MASCHINE-2-Error-Message-Error-NI-Product-could-not-be-loaded-Windows-