https://kb.vmware.com/kb/2144881 - This video demonstrates how to troubleshoot Virtual San 6.2 upgrades which fail after 10% of the upgrade procedure. When upgrading VMware Virtual SAN (VSAN) to version 6.2, the Virtual SAN Disk Format Conversion task fails at 10%. In the vSphere Web Client, you see an error similar to: - A general Virtual SAN system error occurred: Failed to realign following Virtual SAN objects, due to being locked or lack of vmdk descriptor file which requires manual fix. The Convert disk format for Virtual SAN task fails with a General Virtual SAN error status. When upgrading the on-disk format, during the 10% - 15% phase, Virtual SAN realigns objects to prepare them for new features. The process is performed in two steps: - In the first step, Virtual SAN realigns objects and their components to have a 1 MB address space. The process fails in this step if the cluster is unstable or if there is not enough disk space. - In the second step, Virtual SAN realigns vsanSparse objects to be 4k aligned. The process fails if there are objects which cannot be upgraded to version 2.5. An object will fail to upgrade under these conditions: - The object is left behind and no longer referenced by anything. - The disk chain is not complete or is corrupted. For additional information, see: https://kb.vmware.com/kb/2144881