ESXi 4.0 hosts may experience a purple screen after vCenter Server is upgraded to 5.0
Resolution: In vCenter 5.0 Update 1
upgrading from vCenter Server 4.1 to 5.0, the ESX/ESXi 4.1 host fails
with the PSOD error: Spin count exceeded (VASpace) - possible deadlock
with PCPU 2
Resolution: Upgrade to ESX/ESXi 4.1 Update 1 before joining to vCenter 5.x
ESX 4.0 hosts with certain build numbers cannot be managed by vCenter 5.0
A purple screen of death (PSOD) may occur on hosts running ESXi 4.0 releases between Patch03 (build 219382) and Patch09 (build 360236).This occurs when the host is being managed by vCenter 5.0 in a cluster with HA enabled and VPXA agent gets reinstalled on the host e.g. if the host was removed and re-added into the vCenter inventory. With this fix, hosts are allowed to be managed by vCenter and the ESX 4.0 hosts does not PSOD.
This issue is resolved in this release.