Problem taking a snapshot using a backup program

[AndrewGra]

In vSphere I can take a snapshot.
Backup program - XoperoOne cannot execute it.
VCenter returns an error.

Task Name
Create virtual machine snapshot
Status
An error occurred while quiescing the virtual machine. See the virtual machine's event log for details. An error occurred while taking a snapshot: Failed to quiesce the virtual machine. An error occurred while saving the snapshot: Failed to quiesce the virtual machine.

In EVENTS:
Description:
Warning message on FS-2019 on 10.10.1.9 in Datacenter : Failed to start quiescing operation in the virtual machine. The error message was: Error initializing quiesce operation.
Event Type Description:
A warning message listing a collection of observations has been reported by the virtual machine
Possible Causes:
The event contains details on why this warning was issued
Related events:
There are no related events.

The VM has Volume Shadow Copy disabled

[IRIX201110141]

Could you create a quiesced snapshot within vSphere for that VM?  The default snap is a non quiesced.

For me it looks like that you configure your backup programm to take a quiesced one which needs a propper working VSS within the GuestOS.

Enable VSS and configure it properly or just tell your backup program to create a crash consistent one.

Regards,
Joerg

[AndrewGra]

I turned on Volume Shadow Copy and Shared folder. Volume Shadow Copy was turned on previously, but the snapshot did not work. When both are turned on, the snapshot is taken.