Prior to performing the snapshot, make sure that the below prerequisites are applied:
- In vSphere, check that VMware Tools are up and running inside the guest OS. For more information see VMware Knowledge Base: Installing VMware Tools in vSphere
- VSS service is up and running inside the guest OS.
- The problematic VM OS is Windows Server 2003 or higher. Previous versions of Windows, such as Windows XP and Windows 2000, do not include VSS and rely on the SYNC driver. To troubleshoot snapshot issues in these OS, please contact VMware support.
- You are running ESX(i) 4.1 or higher.
Keep in mind the VMware ESX(i) virtualization platform limitations:
- Agent for VMware backs up a fault tolerant machine only if fault tolerance was enabled in VMware vSphere 6.0 and later,
- VMware vSphere does not support snapshots of independent disks and Raw Device Mapping (RDM) disks in physical compatibility mode. To overcome these limitations install an agent into the guest OS.
When the above points are confirmed, please create a manual snapshot of the virtual machine in question as follows:
1. Open the vSphere connection to the ESX host
2. Right click on the machine > take snapshot > check the "Quiesce guest file system"
3. Uncheck the "Snapshot the virtual machine's memory" and click OK
4. Run the snapshot

If you see the error message in the vSphere console, it means the fail occurrs on the VMware (or Microsoft) side. When the snapshot with the above parameters is started, it triggers to run all the VSS writers inside the guest OS. In case if one of the VSS writers is not working properly the quiesced snapshot fails. Complete all steps before proceeding to error troubleshooting step.
If all steps above have been executed and issue still persists, go to error troubleshooting step.