Urbackup destroy my file

i have problem couse in some computer urbackup - i dont know why - change files name i.e.: test.pdf to test.pdf.ivsrsaj and every file with such extension i cant open.
urbackup 1.4.6.
i have this problem on almost 7 laptops.
Any idea?

You might have been infected with CryptoLocker : http://en.wikipedia.org/wiki/CryptoLocker