NBU status: 96, EMM status: No media is available unable to allocate new media for backup, storage unit has none available (96)

I am surprised that you marked your own post as solution.
My guess is that Nicolai and Martin pointed you in the right direction?

You should purchase more media if you do not have enough media.
Manual expiration is never a good idea - retention levels is a business requirement, meaning that backups need to be kept until they natually expire.

BTW - there is no requirement in NBU to label tapes before they can be overwritten.

Status "96, EMM status: No media is available" can origin from 2 possible causes if the VTL is working as intended.

• Either you run out of scratch tape
• The scratch available is the wrong density - e.g configured a HCART2 but the drives are configured as HCART3.

The 185 tapes you mention, what is their status ?. Use the Netbackup GUI under media management, They should either be "full,empty,frozen,suspended". You can also skip the GUI and use a scrip to retrieve media status . See http://www.symantec.com/docs/HOWTO56205

Adding to the outstanding post from Nicolai, here are the details I wrote for a similar issue a short time ago.

 

Media is frozen
Media is not listed as in library
Media retention period is different than backup (by default you cannot put backups of different retention on the same tape)
Media has an expire time set (see vmquery -m "media id" ) (this is not data expire but media expire - has to be set manually )
Media is not the same density as drive
Media is full
Media is frozen
Media is suspended

If you run the available_media script (netbackup/bin/support or goodies ) and you know the retention level of the policy (bpretlevel command) you will probably be able to work it out.

It's possible that NB thinks the media is in use - if no backups are running (or are not active) run :

nbrbutil -resetall

This should force the release of ALL resources (tapes and drives and anything else).

nbrbutil -dump will show what is currently assigned, look under MDS section at the bottom of the output.

This is a useful tool, 96 staus t/shooting wizard:

http://www.symantec.com/business/support/index?page=answers&type=wizard&wizardid=NBU090&wizardstepid=1A&question_box=status+code+96

As Nicolai suggests, if there is some mis-config (eg tape density does not match drive density) then the media might be getting frozen, so if all the media in the VTL is frozen, you likely have a config issue, or some issue that is causing the frozen media.