Arcserve Windows 11.5 backing up NW6.5

The backup fails on 3 open files

1 = sys:\etc\volmn\volmnchk.dat
2 = sys\etc\volmn\volmnchk2.dat
3 = sys\system\certserv\crl.lck

The first two files I've now excluded from the backup.

However I'm unsure about the file "crl.lck"

What are the consequences of not backing it up?

Cheers