I had a problem with my Nexus 7 (2013, 2nd gen) tablet.

I restarted my tablet and when it was rebooting again, it showed "Google" logo and then stood there. I wait it (around 20 minutes) but it did not do anything else.

Trying factory reset... [failed]

I have check many videos that suggesting apply a hard reset or factory reset, so I tried to do this. Once in Recovery mode, I notice that some error messages appear at bottom of screen, they are:

E:failed to mount /cache (invalid argument) E:Can't mount /cache/recovery/log E:Can't open /cache/recovery/log E:failed to mount /cache (invalid argument) E:Can't mount /cache/recovery/last_log E:Can't open /cache/recovery/last_log E:failed to mount /cache (invalid argument) E:Can't mount /cache/recovery/last_install E:Can't open /cache/recovery/last_install E:Failed closing /dev/block/platform/msm_sdcc.1/by-name/misc (I/O error) E:failed to mount /cache (invalid argument) 

Then I selected wipe data/factory reset option and execute it. It started to formatting /databut then similar errores were flushed (here I copy log):

-- Wiping data... Formatting data... E:failed to mount /cache (invalid argument) Formatting cache... E:failed to mount /cache (invalid argument) E:Can't mount /cache/recovery/log E:Can't open /cache/recovery/log E:failed to mount /cache (invalid argument) E:Can't mount /cache/recovery/last_log E:Can't open /cache/recovery/last_log E:failed to mount /cache (invalid argument) E:Can't mount /cache/recovery/last_install E:Can't open /cache/recovery/last_install Data wipe complete. E:failed to mount /cache (invalid argument) E:Can't mount /cache/recovery/log E:Can't open /cache/recovery/log E:failed to mount /cache (invalid argument) E:Can't mount /cache/recovery/last_log E:Can't open /cache/recovery/last_log E:failed to mount /cache (invalid argument) E:Can't mount /cache/recovery/last_install E:Can't open /cache/recovery/last_install E:Failed closing /dev/block/platform/msm_sdcc.1/by-name/misc (I/O error) E:failed to mount /cache (invalid argument) 

Here I show an image of recovery error messages

Trying unlocking device... [failed]

Some pages and forums suggest to flash and install another ROM, I have selected Cyanogenmod and following steps shown inCyanogen wiki page. The first step is unlocking device, this process starts formatting /data and then formatting '/cache', but again it cannot be mounted.

Finally... How can I fix these issue?

Try booting into fastboot and run fastboot format cache and then fastboot erase cache.

I was seeing a very similar issue but in my case the "Formatting ..." step was not followed by a failed to mount message. In my opinion there is a hardware issue with your unit -- if the format fails such that the resulting partition can not be mounted, there's not much that can be done except attempt a warranty repair.