"Unable to connect to MKS" error in vSphere Web Client
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"Unable to connect to MKS" error in vSphere Web Client


Article ID: 340214


Updated On:


VMware vCenter Server VMware vSphere ESXi


  • Launching a virtual machine console from the vSphere Web Client or vSphere Client fails.
  • You see one of these errors.
    • Unable to connect to the MKS: Could not connect to pipe \\.\pipe\vmware-authdpipe within retry period.
    • Unable to connect to MKS: internal error
  • In the /vmfs/volumes/datastore/virtual_machine/vmware.log file, located in the virtual machines directory, you see entries similar to:
<YYYY-MM-DD>T<TIME>| mks| I120: SOCKET 5 (122) recv error 104: Connection reset by peer
TIME>| mks| I120: SOCKET 5 (122) VNC Remote Disconnect.
TIME>| mks| W110: SSL: Unknown SSL Error
TIME>| mks| I120: SSL Error: error:14094418:SSL routines:SSL3_READ_BYTES:tlsv1 alert unknown ca
TIME>| mks| I120: SSL Error: error:140940E5:SSL routines:SSL3_READ_BYTES:ssl handshake failure
  • In the /var/log/hostd.log file, you see entries similar to:

    <YYYY-MM-DD>T<TIME> info hostd[28CC1B70] [Originator@6876 sub=Vmsvc.vm:/vmfs/volumes/5524009b-6ab4ce54-6fb0-001a64dda48a/vc/vc.vmx opID=fe5a38b5-5f95-4ca5-83f5-df6def1268f3-199-ngc-a8-33-db97 user=vpxuser:<domain>\Administrator] Ticket issued for mks service to user: vpxuser
    [LikewiseGetDomainJoinInfo:355] QueryInformation(): ERROR_FILE_NOT_FOUND (2/0)

    Note: The preceding log excerpts are only examples. Date, time, and environmental variables may vary depending on your environment.
  • When migrating an ESXi host to a new vCenter Server, the SSL certificate may change.


VMware vCenter Server 6.0.x
VMware vSphere ESXi 6.0


This issue occurs because an ESXi host is not placed in maintenance mode before migrating to a different vCenter Server.


This issue is resolved in VMware ESXi 6.0 Update 2, available at VMware Download

To work around this issue, refresh the VMX/MKS SSL cache on the virtual machine by migrating the virtual machine to another ESXi host.
If migrating the virtual machine does not resolve the issue, reboot the ESXi host.

To reboot the ESXi host:
  1. Power off the affected virtual machine.
  2. Place the ESXi host into maintenance mode.
  3. Restart the ESXi host.

Additional Information

For more information, see: