this artical expains How and where to collect diagnostics for VMware quiesced snapshot failures on windows VM when backing up with netvault backup
1/ enable VDDK trace see linked solution of go to URL below to see how this is done.
2/ enable trace on the netvault server or client ware the plugin is installed to do this see URL below.
3/ run failing backup
4/ disable trace netvault and VDDK
5/ supply the following:
vixDiskLib-xxxxx.log On windows system the log files are found C:\WINDOWS\Temp\vmware-SYSTEM
zipped copy of the …/netvault/trace directory
binary log of the failing backup
vpxa.log In VMware Infrastructure 3.x and vSphere 4.x, the log is located at /var/log/vmware/vpx/ In vSphere 5.0, the log is located at /var/log on ESX server.
vmware.log from the data store directory of problem VM
6/ system and application event logs from failing windows VM