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Hyper-V CBT error CBTDriverError:uvbCbtSnapshotCreationStarted - Connect IT Community | Kaseya
<main> <article class="userContent"> <h2 data-id="summary"><strong>SUMMARY</strong></h2> <p>CBT drive on a Hyper-V cluster can get out of sync. This can cause CBT issues with getting changed blocks resulting in incremental backups that are the same size of a full backup.</p> <h2 data-id="issue"><strong>ISSUE</strong></h2> <p>----- Error Messages -----<br>CBTDriverError:uvbCbtSnapshotCreationStarted:: FFFFFFFF80070002<br>Due to previous error, Unitrends agent is not able to use the Hyper-V CBT filter driver during backup job for VM {A4C9989D-86C9-4769-81FE-E8765E5B6691}: all files will be backed up as full not change blocks.<br>----- End Error Messages -----</p> <h2 data-id="resolution"><strong>RESOLUTION</strong></h2> <p>Open the following file in notepad and review the <strong>Sync Status </strong>line on each Hyper-V node in the cluster.</p> <pre class="code codeBlock" spellcheck="false" tabindex="0">C:\unicbt\config\in.xml</pre> <p>You will see if the drive is <strong>InSync</strong> or <strong>NoSync or OutSync </strong>like the following.</p> <pre class="code codeBlock" spellcheck="false" tabindex="0"><CBT> <VERSION>2</VERSION> <SYNC_STATUS>NoSync</SYNC_STATUS></pre> <p>If the driver is out of sync you will want to <strong>stop</strong> the CBT (<strong>UnitrendSVC</strong>) service on each Hyper-V node.<br><br><img src="https://us.v-cdn.net/6032361/uploads/migrated/GZPAG951H66D/eid-ka01w000000g2an-feoid-00n40000003czqx-refid-0em1w000000rl0z." alt="User-added image" width="500" height="269" class="embedImage-img importedEmbed-img"></img><br><br>Once the <strong>UnitrendSVC</strong> service is stopped on each node, <strong>start </strong>the <strong>UnitrendSVC</strong> on each node to complete the sync CBT. <br><br><img src="https://us.v-cdn.net/6032361/uploads/migrated/WAA7E98NGNHA/eid-ka01w000000g2an-feoid-00n40000003czqx-refid-0em1w000000rl14." alt="User-added image" width="500" height="257" class="embedImage-img importedEmbed-img"></img><br>Perform <a href="/home/leaving?allowTrusted=1&target=https%3A%2F%2Fkaseya.vanillacommunities.com%2Fkb%2Farticles%2Faliases%2Funitrends%2Fhc%2Fen-us%2Farticles%2F360013266778" rel="noopener nofollow">an Inventory Sync</a>. This pulls the most current inventory to update our database. Lastly, take another Hyper-V full backup which, once completed, should remedy the incremental backup size issues moving forward.</p> <p> </p> <p> </p> <h2 data-id="cause"><strong>CAUSE</strong></h2> <p>CBT drive loses sync with the other cluster nodes which requires a reset to get the driver back in sync.</p> </article> </main>