Вот такая вот штука при emerge gnome:
# emerge gnome
Calculating dependencies... done!
>>> Verifying ebuild Manifests...

>>> Emerging (1 of 100) net-print/cups-1.3.8-r2 to /
!!! Previously fetched file: 'cups-1.3.8-source.tar.bz2'
!!! Reason: Filesize does not match recorded size
!!! Got: 3978466
!!! Expected: 3978390
Refetching... File renamed to '/usr/portage/distfiles/cups-1.3.8-source.tar.bz2._checksum_failure_.IZXMSo'

>>> Downloading 'ftp://mirror.corbina.net/pub/Linux/gentoo/distfiles/cups-1.3.8-source.tar.bz2'
--16:35:13-- ftp://mirror.corbina.net/pub/Linux/gentoo/distfiles/cups-1.3.8-source.tar.bz2
=> `/usr/portage/distfiles/cups-1.3.8-source.tar.bz2'
Resolving mirror.corbina.net... 195.14.50.21
Connecting to mirror.corbina.net|195.14.50.21|:21... connected.
Logging in as anonymous ... Logged in!
==> SYST ... done. ==> PWD ... done.
==> TYPE I ... done. ==> CWD /pub/Linux/gentoo/distfiles ... done.
==> PASV ... done. ==> RETR cups-1.3.8-source.tar.bz2 ... done.
Length: 3 978 466 (3.8M) (unauthoritative)

100%[==================================>] 3 978 466 6.89M/s

16:35:15 (6.89 MB/s) - `/usr/portage/distfiles/cups-1.3.8-source.tar.bz2' saved[3978466]

* checking ebuild checksums ;-) ... [ ok ]
* checking auxfile checksums ;-) ... [ ok ]
* checking miscfile checksums ;-) ... [ ok ]
* checking cups-1.3.8-source.tar.bz2 ;-) ... [ !! ]

!!! Digest verification failed:
!!! /usr/portage/distfiles/cups-1.3.8-source.tar.bz2
!!! Reason: Filesize does not match recorded size
!!! Got: 3978466
!!! Expected: 3978390

Что значит "не соответствует зарегистрированному размеру"?