Troubleshooting ShadowSnap Backups



This article provides procedures to troubleshoot ShadowSnap backups, including slow backup transfer speeds.


  • Datto SIRIS
  • Datto ALTO
  • ShadowSnap Agent


Ensure the ShadowSnap Agent is up to date. Find the latest ShadowSnap version information here

Check Show Agent Logs to Find the Causal Error

  1. Log into the device's web interface.
  2. Click on the Protect tab.
  3. Search the agent list for the machine with the issue, and click Show Backup Logs.
  4. Then, click Show Agent Logs.
  5. Find the earliest red line: This indicates the cause of the error.
  6. Use some key words from that error to search this KB for that error.
    Note: Disregard anything that has an IP or an extremely long GUID. You are looking for anything that can be specific to the production machine. 
  7. Follow the KB article for a solution to the problem.

Check Connectivity

These are some common connectivity issues. For a full discussion of network issues, see Datto Networking Requirements.

  • Verify that port 25566 is open. If the StorageCraft Raw Agent Service is not running, this port may appear as closed.
  • Verify that no antivirus or firewalls are blocking ShadowSnap or Port 25566.
  • If the device is on a domain, verify that proper domain permissions have been put in place.

Check Services

Open services.msc on the target machine. Check for these services:

  • ShadowProtect Service
  • StorageCraft Raw Agent
  • StorageCraft Shadow Copy Provider

If the services are not running, start them. If they are running, try these steps:

  1. Stop the services.
  2. Make sure no associated processes are running in Task Management. The processes are:
    •  raw_agent_svc.exe
    •  ShadowProtectService.exe
    •  ShadowProtect.exe
    •  vsnapvss.exe
  3. Restart the services.

Check ShadowProtect software

Follow these steps to verify that you have the correct version of ShadowProtect on your target machine:

  1. Make sure the local device is selected in ShadowProtect interface. Then, check in the lower left that the license appears as active.
  2. Go to the Help menu, and click About. Verify that you are running the MSP version of ShadowProtect and that it is currently the latest version of the software, which is version 5.0.1.X MSP.
  3. Make sure that there are no ShadowProtect backups either scheduled or running.

Check VSS Status

Follow these basic steps:

  • From a command prompt, type in vssadmin list writers.
    This will return the state of the VSS writers.
    If a backup is in process, you will see a status of waiting for completion. Otherwise, all writers should return stable and healthy.
  • If VSS Writers are in failed or unknown states, they can be cleared using VShadow against the OS volume as described in the article on VShadow.
  • Commonly found conflicting VSS services can also cause issues with the VSS backups taken by ShadowSnap.

See VSS Explained for more information.

Troubleshooting Slow Backups

This section gives potential causes and solutions for slow backups.

Potential Causes

These can all contribute to slow backups:

  • Local network traffic is high.
  • Local server activity is high or available resources are low.
  • NICs are not properly configured to best handle network traffic.
  • Physical connections to the device have hardware damage.
  • Protected servers have disk errors or are heavily fragmented.


Follow these steps to troubleshoot slow backups.

Check the Network

  1. Local network traffic. Analyze the traffic usage on your protected server as well as the available resources on the server. StorageCraft has an article discussing best practices for improving the reliability of backups. The most important aspects of this article to consider are page file locations, large send off-loads, as well as memory management keys. Many of these recommendations will require reboots of the target machine.

  2. If you are using a virtual product (vSIRIS, vALTO), check your hypervisor's documentation for instructions on how to optimize your virtual NICs:
  3. Test the physical network connections, including cable connectors. Check the health of the physical server NICs with any diagnostic tools provided by the NIC manufacturer. Verify the speed of the NICs from the Network tab on the device interface. All Datto device NICs are at gigabit speed. Verify that the switch the network cable is plugged into supports a gigabit connection. NICs can also be bonded or teamed on the local Datto device should your switch support link aggregation to improve local throughput. Check to see if the protected system can access other shares on the network. Running the following command sets from an elevated Windows Command Prompt session can help with the diagnostic process:

    Diagnosing Network Health
    wmic NIC where NetEnabled=true get Name, Speed Checks the agent's NIC for a gigabit connection and whether the agent backed up over a WAN
    net statistics workstation confirm there are no network errors and raw read/write denied errors
    ping (datto name/ip) Are there high ping times?
    tracert (datto name/ip) Are there several hops?

Check Hard Drive Health

  • If you continue to experience slow transfer speeds, check the physical health of the disks and RAID with disk cleanup and defragmentation utilities. If you find disk errors or high fragmentation, schedule a chkdsk /r and defragmentation. Running the following command sets from an elevated Windows Command Prompt session can help with the diagnostic process:

    Diagnosing Hard Drive Health
    Command Description
    wmic diskdrive get status Reports SMART status health
    defrag (volume letter): /A Analyze volumes for disk fragmentation percentages
    winsat disk -drive (volume letter) Analyzes volume read/write speeds
    wevtutil qe System “/q:*[System[(Level=1 or Level=2)]]” /f:text /RD:TRUE /C:10 Review system logs for the last 10 level 1 and 2 errors

Review Agent Logs

  1. Go to the web interface for the device. Go to the Protect link, scroll to agent, and find the Backup Logs link on the left. Click the link to see the logs.

  2. Search the Datto Knowledge Base to find information more specific to the root cause of your error.

  3. Review the StorageCraft server tuning guide for additional advice.

Further Steps

If the previous sections did not help you solve the problem, here are some other things to try:

  • You can test ShadowProtect backups by running them to a NAS share on the device or any other network storage target to see if you can replicate the error in ShadowProtect.
  • StorageCraft’s knowledge base directly references a number of errors that can be found within the ShadowProtect software.
  • Contact Datto Tech Support.

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