I'm on 12.04 and an update last week seems to prevent me from using apt-get.

drew@drew-desktop:~$ sudo apt-get -f install
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Correcting dependencies... Done
The following extra packages will be installed:
The following NEW packages will be installed:
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 348 kB of archives.
After this operation, 1,111 kB of additional disk space will be used.
Do you want to continue [Y/n]? Y
Get:1 http://us.archive.ubuntu.com/ubuntu/ precise-updates/main gvfs-daemons amd64 1.12.1-0ubuntu1.1 [348 kB]
Fetched 348 kB in 0s (483 kB/s)       
dpkg: error processing /var/cache/apt/archives/gvfs-daemons_1.12.1-0ubuntu1.1_amd64.deb (--unpack):
 gvfs-daemons: 1.12.1-0ubuntu1.1 (Multi-Arch: foreign) is not co-installable with gvfs-daemons:amd74 1.12.1-0ubuntu1.1 (Multi-Arch: foreign) which is currently installed
Errors were encountered while processing:
E: Sub-process /usr/bin/dpkg returned an error code (1)
I'm a bit confused by this. Why is it trying to install a NEW version of gvfs-daemons when I apparently already have it installed? This prevents me from installing anything else. I've tried the dance of dpkg --configure -a and apt-get -f install and nothing lets me get past this particular package. I added a ppa this weekend but I have since removed it. Is there a way to figure out what package is demanding that gvfs-daemons be updated so that I can either deselect it or remove it? I'm not super familiar with all the dpkg/apt-get commands so thanks in advance for any help!