On PowerLink please see Support Solution emc254967 - this lists all of the articles about Host Agent. There might be one that answers your question.  To de-register a host, the host must not be in a storage group, the paths from the host must not be logged in. Then from Conectivity Status you should be able to de-register the host (deregister each path). You also should try stopping Agent on the host before you try this.  One thing you can try first is to restart Management Server on both SPA and SPB first. Sometimes the GUI does not reflect the actual the state of the hosts, especially if there are have changes.  The name of the two files, agentID.txt and HostIdFile.txt are case sensitive - be careful with the names.  glen
Hi, I have a problem with EMC VNX5500 storage. I have a host with multiple IP's, it were added and registered when its ip were reachable from storage system. A while ago our network configuration changed and its ip now unreachable, so in Unisphere web-interface host were showing as "unmanaged / host agent unreachable or connection registered manually..." Now i need to remove it and re-register (to fix ip's and to learn the procedure - soon i'll be needed to connect another host and need to test whole procedure), but it seems i cannot do that - "remove" option is masked/disabled. I removed host from storage group - no effect; started hostagent with new correct Hostid.txt and agentID.txt - no effect; tried to "connect host" - entered new ip - no effect;  tried to edit host record in "connectivity status" - selected both hba's, checked "this hba's belong to new host" and entered same hostname and new ip - now both hba connections dissapeared from "connectivity" windows, host show in status "inactive/unmanaged/host agent unreachable". And i still cannot remove it. I even tried to disable ports on FC-switches to physicly disconnect host from storage - still no effect, cannot remove host. Also, there are 2 alerts with error code 0x721b shown...  Now this host have physical connection to storage, but cannot access any of its lun's, as i cant do anything with current host record and i cant register new record for this host - not by hostagent, not by server utility, not manually. Please provide some assistance, how to remove host and re-register it ?
How to delete manually-registered host