Status 129 - even when we have free space in Disk

Hi Team,

We are using Symentac Netbackup 7.1.0.4.

For past 6 months i have noticed, some time we backup failure for status 129 while taking a backup of C:\Windows\System32\drivers\etc\hosts .

I ensured that we have enough free space in the DISK.

But in the second attempt automatically it completes fine.

Could you please help me how to resolve this issue.