Error: HA agent fails to install when adding ESXi host to cluster

Products

• VMware vSphere ESXi

Issue/Introduction

• ESXi host cannot be added to the cluster. 
• Error: Unable to access the Datastore to install HA Agent

 

Environment

• VMware vSphere ESXi 8.x

Cause

• Corrupted vmfs Datastore is preventing HA agent to be installed on the ESXi host. 
• Corrupted vmfs Datastore is preventing host from being added to the cluster. 

 

• /var/log/vmkernel.log reports logging similar to:

2026-05-12T13:02:46.881Z cpu8:2511757)WARNING: Fil3: 1638: Failed to reserve volume <VMFS UUID>
2026-05-12T13:02:46.881Z cpu8:2511757)Vol3: 4768: Failed to get object 28 type 2 uuid <VMFS UUID> FD 4 gen 1 :No filesystem on the device
2026-05-12T13:02:46.908Z cpu8:2511757)WARNING: Vol3: 2423:  <DatastoreName> has severely corrupted

 

Resolution

Fix corrupted datastore by following instructions from the below KB article. 

Using vSphere On-disk Metadata Analyzer (VOMA) to check VMFS metadata consistency

 

 

Additional Information

Workaround:

1. Unmount the corrupted datastore from the ESXi host 

2. If it is not possible to unmount corrupted datastore then it has to be unmapped/unpresented from affected ESXi host. 

3. Once the corrupted Datastore is unmapped, joining the host to the cluster is possible.