CVVD.SYS driver may cause reboot when using Live Browse or Block Level restore using Virtual Server Agent

  • 5 November 2021
  • 6 replies

Userlevel 5
Badge +10

An edge condition was found when performing a file-level restore of a virtual machine using the Virtual Server Agent, the Access or Proxy Node may reboot due to the CVVD.sys driver that loads the backup data for browsing.

The following versions are affected:

  • FeatureRelease 22.42 to 22.49
  • FeatureRelease 23.29 to 23.34
  • FeatureRelease 24.15 to 24.20
  • FeatureRelease 25.0 to 25.2

Some common symptoms are the CVD log will flood with NULL values and the following error will be reported for the browse on the media agent.

Failed to receive browse response from MediaAgent. Please check Browse.log on MediaAgent.

The Browse log on the media agent and\or access node (VSA Proxy) may indicate the following:

CCvNetwork::CheckIfDataAvailable() - Thread is waiting for data on a socket. Waited for 600 sec(s). Requested wait time = no time out. Connection details :


The CVVD challenge is addressed with the latest maintenance releases when applied to the Virtual Server Proxy or Access Node. These can be downloaded and installed using the CommCell Console. More information on the update process can be found here: Installing Maintenance Releases Using the CommCell Console

Links to the latest individual maintenance releases for specific Feature Releases:

If you are unable to update to the most current Maintenance Release, you can download and install the individual hotfixes.
The individual hotfixes can be Copied into the CommServe Cache which will enable them to be pushed out to the needed machines.

Bug Symptoms: CVVD driver may crash on VSA/BL live restores

6 replies

Userlevel 5
Badge +13

Hi, just wanted to make sure that FR21 is not affected by this, as it’s not listed. Can someone confirm ?

Userlevel 5
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Issue occurs in the listed versions only.

Userlevel 5
Badge +13

Thanks Liam for the clarification :thumbsup_tone1:


If I am at 11.21.58 can I go directly to 25.2?

Userlevel 7
Badge +23

If I am at 11.21.58 can I go directly to 25.2?

of course!


FYI to JayPena & others: if you update to FR 24 or later there is a change in FR24 that installs the storage accelerator if you are using cloud storage in your storage policies.

It’s easiest to just globally push that out ahead, or you may be surprised by an auto-deployment after your upgrade. It is a benign add-on from my experience. I’ve otherwise jumped versions like this with no problems.