Dtyjlui

Ubuntu 12.04 is not able to mount /home partition and I run:

fsck /dev/sda5

which is in state

Pass 1D: Reconciling multiply-claimed blocks

(There are 41608 inodes containing multiply-claimed blocks.)

And then it is a question:

Clone multiply-claimed blocks<y>?

What should I do? Keep pressing Yes it could take weeks till go through all 41608 inodes.
There is some data in the /home partition that I would like to save.
Do I have more options to recover this partition?

Thank you

[EDIT]

Start confirming (by clicking 'y') and on some of them I've got the following:

clone_file_block: internal error: can't find dup_blk for 121143344

[UPDATE-01]
after David's answer and booting live system image of Ubuntu 14.10-beta Utopic...
and running

e2fsck -p /dev/sda5

I've got the following:

/dev/sda5 contains a file system with errors, check forced.

/dev/sda5: Root inode is not a directory. /dev/sda5: UNEXPECTED INCONSISTENCY;

run fsck MANUALLY. (i.e. without -a or -p options)

Advisory note: It would be a very good idea to backup the entire file system before performing any changes or fixes to it. If you don't have enough space for that use e2image(8) as an emergency precaution.

Fixing corrupt superblocks [Edit]

According to your comment you have a corrupt file system superblock. There's an answer on serverfault that deals with this.

Since it's impossible to find the correct block size without a working superblock, I would guess from the volume size of 400 GB that the block size is 4 KiB, which leads to a superblock backup position of 32768. Therefore

e2fsck -b 32768 -p /dev/sda5

and then take it from there depending on the output.

Fighting the repetitive user interaction requests

I pulled the following from the e2fsck(8) manual:

-p     Automatically  repair  ("preen")  the  file system.  This option

       will cause e2fsck to automatically fix any  filesystem  problems

       that  can be safely fixed without human intervention.  If e2fsck

       discovers a problem which may require the  system  administrator

       to  take  additional  corrective  action,  e2fsck  will  print a

       description of the problem  and  then  exit  with  the  value  4

       logically  or'ed  into  the  exit  code.   (See  the  EXIT  CODE

       section.)  This option is normally used  by  the  system's  boot

       scripts.   It may not be specified at the same time as the -n or

       -y options.



-y     Assume  an answer of `yes' to all questions; allows e2fsck to be

       used non-interactively.  This option may not be specified at the

       same time as the -n or -p options.

The -p-option is the safer route in case there are other serious errors, but if that doesn't work, try -y.

clone_file_block error

This appears to be a known bug. You can try your luck with a newer version of the e2fsprogs packages from the pre-release Utopic series through Launchpad or with a live system image.