You can have files with different rights anywhere on your system. One thing you can do is nuke that build folder then use chown and chmod on the content of your download folder and ensure that everything belongs to the correct user and with read/write properties.

Hi, I still got this issue on Qt 6.8.3. Anyone has found some way to resolve this problem? Thanks! Error setting up serial port /dev/tty.usbmodemCACF62D63C042. open: Operation not permitted

ok, that's it :-) With strace I found out the problem was a lock in /var/lock I removed this now its working. Thanks a lot