This article describes preliminary troubleshooting steps for Windows backup errors or warnings. When you have any kind of error or warning with the ShadowSnap agent, start with these steps. If the steps listed here do not solve the problem that you are having, refer to Section 5 for advice on specific backup errors.
Figure 1 - Example of a backup error
2. Check ShadowSnap and ShadowProtect
This section describes common troubleshooting procedures that you should follow for any ShadowSnap backup error.
If this is a new deployment, review our guide on Preparing for ShadowSnap deployment, as this covers a wide span of best practices you should follow regarding specific server configurations which are beyond the scope of this article.
If backups were functioning previously, consider the environment this device and agent are deployed in. Is there any maintenance occurring, or have there been any recent changes to the protected machine or its network be the cause of these errors? If the health of a protected system or its environment is weakened, it's highly likely that the reliability of backups will decrease as well.
2.1. Check your ShadowSnap version
First, check that the protected machine is using the latest version of ShadowSnap. Many transient errors that were present in earlier versions of ShadowSnap and ShadowProtect were fixed in the latest version.
To check the version of ShadowSnap, go into the device's Remote Web interface, and click on the Protect tab. Scroll to the machine that you are troubleshooting. Then, check the agent version, as shown in Figure 2.
Figure 2 - ShadowSnap agent version, as shown in Remote Web
2.2. Check your ShadowProtect version
To make sure you have the latest version of ShadowProtect on the target machine, open the StorageCraft ShadowProtect program from Windows Explorer. Go into the Help menu, and click About, as shown in Figure 3.
Figure 3 - Checking the version of ShadowProtect
If ShadowProtect is not at version 126.96.36.19957 or above, proceed to the next section to reinstall.
2.3. Upgrading ShadowProtect and ShadowSnap
If either ShadowSnap or ShadowProtect are out of date, we recommend that you uninstall, downloading the latest versions, and reinstall both ShadowProtect and ShadowSnap. Here is the detailed procedure:
- Go into Add or Remove Programs. Uninstall both ShadowProtect and ShadowSnap.
- Reboot the server.
- Reinstall ShadowProtect and ShadowSnap using the latest installers available at download.datto.com.
- Reboot the protected machine to load the agent before backups may resume.
3. Restart agent services
Some backup errors may result when the ShadowSnap agent services are not running properly.
Check that all 3 services are present on the target machine via services.msc:
- StorageCraft Raw Agent
- StorageCraft Shadow Copy Provider
- ShadowProtect Service
Open up task manager, and end the processes of any instances of the following services:
Restart the services through the services.msc console.
4. Repair agent communications
This simple step forces the Datto device to redo the handshake that occurs during initial agent pairing. This also refreshes some important configuration keys on the device's end, and can solve a number of agent communication errors.
- On the Datto device, navigate to Protect > Configure Agent Settings.
- Scroll to the bottom of the Configure Agent Settings page, and click the Repair Agent Communications button, as shown in Figure 4.
Figure 4 - Repair Agent Communications
5. Next steps
If these preliminary troubleshooting steps do not solve your problem, refer to the list below for a link to an article about the specific error you are seeing:
Common Critical Errors
- Unable to start backup because agent is unreachable
- Backup skipped due to not enough free space
- A backup hasn't been taken in over 24 hours
- Unable to start backup because agent service is stopped.
- Backup failed as Backup job was unable to be assigned
- VSS Export error occurred mid-transfer - falling back to STC
- The backup job stalled longer than 900 seconds and was cancelled
- Agent driver is not loaded. Please restart this system to load the driver.
- homePool/home/agents/[agentName] is not mounted, cannot proceed with backup
- Backup error "Backup requested but an old backupRequest still exists!"
STC/VSS failure occurred mid transfer
- The .datto file is not found or not accessible / Bad HTTP Error 500
- error code -121 / Final error (-121 The semaphore timeout period has expired.)
- (6, 'closehandle', 'the handle is invalid.')
- stcx.SnapshotError: HSR Commit failed after 3 attempts.
- Final error (-50 The request is not supported.)
- Final error (-1392 Invalid data format.)
- Final Error (-2 The System Cannot Find The File Specified.)
- Write error (-31 A device attached to the system is not functioning.)
- Snapshot returned error code -1450
- Final error (-32 The process cannot access the file... used by another process.)
- Final error (-53 The network path was not found.)
- [Errno 13] Permission Denied
- Unexpected End Of The Image File
- [Errno 4] Interrupted function call
- Volume GUID Mismatch
- Fatal I/O error on .datto: #112 on write: there is not enough space on the disk
- Final error (-5 Access is denied.)
- Final Error (#31 A device attached to the system is not functioning.)