When updating a system or installing a new program users may run into "blockers". Blockers in Gentoo ebuilds simply mean that two packages cannot be installed at the same time on the same system.
When upgrading, these are usually packages that have been superseded by other packages. And this is unfortunately common with names for libraries that are too generic. For example, libnw could be either dev-games/libnw or sci-biology/newick-utils.
[blocks B ] app-mobilephone/obex-data-server ("app-mobilephone/obex-data-server" is blocking app-mobilephone/obexd-0.43-r1) [blocks B ] app-mobilephone/obexd[server] ("app-mobilephone/obexd[server]" is blocking app-mobilephone/obex-data-server-0.4.5) * Error: The above package list contains packages which cannot be * installed at the same time on the same system. (app-mobilephone/obex-data-server-0.4.5::gentoo, ebuild scheduled for merge) pulled in by >=app-mobilephone/obex-data-server-0.4.5 required by (gnome-base/gvfs-1.10.1::gentoo, ebuild scheduled for merge) (app-mobilephone/obexd-0.43-r1::gentoo, ebuild scheduled for merge) pulled in by app-mobilephone/obexd required by (net-wireless/gnome-bluetooth-3.2.1::gentoo, ebuild scheduled for merge)
Removing the blocker in this case is as simple as removing the
server USE flag from wherever it is referenced (make.conf, package.use, or some other location).
Resolutions will not always be this simple. Be diligent in reading Portage output to determine how to resolve blockers.
- USE flags section in the AMD64 Gentoo Handbook