Hello,  Try the following in this exact order:  Hopefully this helps
Hoping someone out there has run into and resolved this issue. Have not been able to find any reference to this problem on the inter-webs...  While performing the vCenter Plugin install after the step that asks you to log out and back in to the vsphere web client and press enter I am receiving the following:  -------- Log out, and then log back in to vSphere web client. The plugin is downloaded upon login to the vSphere web client. After you have logged back in, press ENTER.  ERROR: The process with PID 6096 could not be terminated. Reason: There is no running instance of the task. Disconnecting from the vCenter XXX.XXX.XXX.XXX... --------  I have attempted the install from 2 separate systems both 32-bit and 64-bit Java installs from both 32/64bit PowerCLI prompts in all combinations. All components are fully updated (versions listed below). And install method is of plugin is the standard option, firewalls turned off and the machines that attempted performing the install are on the same subnet as the vCenter appliance  vCenter Appliance: 6.5.0.12000 Windows Server 2016  java version "1.8.0_151" Java(TM) SE Runtime Environment (build 1.8.0_151-b12) Java HotSpot(TM) 64-Bit Server VM (build 25.151-b12, mixed mode)   The error that is constantly repeated in the Scaleio.log is below. The log ends abruptly with this being repeated a random number of times: ---------- 2017-11-28 11:32:46,061 [Thread-2] ERROR c.e.s.s.services.GeneralServiceImp - mdm.ip.addresses is missing 2017-11-28 11:32:46,061 [Thread-2] ERROR c.e.s.a.mdm_proxy.MdmProxyServiceGW - in ScaleIo alert poller: java.lang.NoClassDefFoundError: Could not initialize class com.emc.s3g.scaleio.lockbox.LockBoxService at com.emc.s3g.scaleio.services.GeneralServiceImp.getMdmUsername(GeneralServiceImp.java:242) ~[ams-1.0-SNAPSHOT.jar:na] at com.emc.scaleio.ams.mdm_proxy.MdmProxyServiceGW$MdmPoller.run(MdmProxyServiceGW.java:487) ~[ams-1.0-SNAPSHOT.jar:na] at java.lang.Thread.run(Unknown Source) [na:1.8.0_151] 2017-11-28 11:32:46,342 [http-nio-65101-exec-4] INFO  c.e.s.s.w.controller.UtilController - Downloading the Plugin file 'EMC-ScaleIO-vSphere-web-plugin-2.0.13000.211.zip' from 'C:\Users\Administrator\Desktop\ScaleIO\gatewayServer\webapps\ROOT\resources' (XXXXXXXXXXX-XXXXXXXXXXX) 2017-11-28 11:32:47,076 [Thread-2] ERROR c.e.s.s.services.GeneralServiceImp - mdm.ip.addresses is missing 2017-11-28 11:32:47,076 [Thread-2] ERROR c.e.s.a.mdm_proxy.MdmProxyServiceGW - in ScaleIo alert poller: java.lang.NoClassDefFoundError: Could not initialize class com.emc.s3g.scaleio.lockbox.LockBoxService at com.emc.s3g.scaleio.services.GeneralServiceImp.getMdmUsername(GeneralServiceImp.java:242) ~[ams-1.0-SNAPSHOT.jar:na] at com.emc.scaleio.ams.mdm_proxy.MdmProxyServiceGW$MdmPoller.run(MdmProxyServiceGW.java:487) ~[ams-1.0-SNAPSHOT.jar:na] at java.lang.Thread.run(Unknown Source) [na:1.8.0_151] 2017-11-28 11:32:48,217 [Thread-2] ERROR c.e.s.s.services.GeneralServiceImp - mdm.ip.addresses is missing 2017-11-28 11:32:48,217 [Thread-2] ERROR c.e.s.a.mdm_proxy.MdmProxyServiceGW - in ScaleIo alert poller: java.lang.NoClassDefFoundError: Could not initialize class com.emc.s3g.scaleio.lockbox.LockBoxService at com.emc.s3g.scaleio.services.GeneralServiceImp.getMdmUsername(GeneralServiceImp.java:242) ~[ams-1.0-SNAPSHOT.jar:na] at com.emc.scaleio.ams.mdm_proxy.MdmProxyServiceGW$MdmPoller.run(MdmProxyServiceGW.java:487) ~[ams-1.0-SNAPSHOT.jar:na] at java.lang.Thread.run(Unknown Source) [na:1.8.0_151] ----------  Would appreciate any insight, Thanks!
Install of ScaleIO Plugin fails - vCenter 6.5