Getting Signature Outdated Warning

Hello Dave.

A couple of days ago I started getting the "...signatures are outdated." warning. Following the instructions on the github project page I issued a "find" and this only listed one folder; "/var/lib/clamav$". I have:

-rw-r--r-- 1 clamav clamav 402K Mar 8 17:44 bytecode.cld
-rw-r--r-- 1 clamav clamav 383K Jan 31 09:25 bytecode.cld.broken
-rw-r--r-- 1 clamav clamav 115M Mar 13 20:32 daily.cld
-rw-r--r-- 1 clamav clamav 102M Nov 3 22:33 daily.cld.broken
-rw-r--r-- 1 clamav clamav 62M Feb 20 17:43 main.cvd
-rw-r--r-- 1 clamav clamav 62M Nov 5 23:59 main.cvd.broken
-rw------- 1 clamav clamav 208 Mar 16 21:58 mirrors.dat

Following a manual signature update, you can see that only "mirrors.dat" was the only file downloaded at the current time (today is 16th March). "daily.cld" was last updated on 13th March, possibly coincidentally the last day I didn't get the warning.

Are the presence of ".broken" files responsible for the warning?

This has happened on both my machines, even though they're on different subnets.
One machine is running Linux Mint 17.x
One machine is running WattOS 9

Both are built over the Ubuntu Trusty LTS base.

I'm not really sure why this started happening. Please could you shed some light if possible?

Thanks a lot,
Mike.