libusb: libusb-1.0.0.dylib already exists and does not belong to a registered port

[XE3ADC (Abraham Diaz de Leon)]

Hello, i encountered an error during the installation of GNURADIO port v 3.7.13.5 on OSX El Capitan, Xcode v8.2, could you please help me to correct this issue to be able to have a correct installation of GNURADIO?
down below is the error description obtained from the console,
Thanks in advance and best regards,
Abraham Diaz de Leon Camou
Villahermosa - Tabasco - Mexico

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Console output:
--->  Fetching archive for libusb
--->  Attempting to fetch libusb-1.0.23_0.darwin_15.x86_64.tbz2 from https://packages.macports.org/libusb
--->  Attempting to fetch libusb-1.0.23_0.darwin_15.x86_64.tbz2.rmd160 from https://packages.macports.org/libusb
--->  Installing libusb @1.0.23_0
--->  Activating libusb @1.0.23_0
Error: Failed to activate libusb: Image error: /opt/local/lib/libusb-1.0.0.dylib already exists and does not belong to a registered port.  Unable to activate port libusb. Use 'port -f activate libusb' to force the activation.
Error: See /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_devel_libusb/libusb/main.log for details.
Error: Follow https://guide.macports.org/#project.tickets to report a bug.
Error: Processing of port gnuradio failed

[kencu (Ken)]

The basic issue is that this file:

/opt/local/lib/libusb-1.0.0.dylib

somehow exists in that location, but MacPorts doesn't know how it got there. The port that is supposed to provide that file already finds it there -- and now asks you what you want to do.

You probably want to follow the instruction to force over-write it with the one MacPorts wants to install.

You might ask yourself how it could come to be that that file is there, however. It is not supposed to be there...

[ryandesign (Ryan Carsten Schmidt)]

If you cannot explain why this file was already there when MacPorts did not install it, then perhaps other files were also installed into the MacPorts prefix by something other than MacPorts (perhaps by some installer you ran?) and if so you would likely run into this problem again in the future with other ports. You may need to uninstall MacPorts and all ports and then reinstall the ports you want to get back to a consistent state. If you can remember running and installer that put this file there, then you should advise whoever distributed that installer that they should change where their installer installs files so that it does not conflict with MacPorts.