When old ISO's remain uncleaned on vSphere, VUM fails the latest upgrades in case the ISO is recognized as a duplicate to the current ISO during import stage and user needs to manually delete the older ISO on vSphere UI.
ESXi upgrade fails at stage ESX_UPGRADE_VUM_STAGE_REGISTER_UPLOADED_FILES stage.
Error on UI: High: Multiple ISO files imported on VUM.
There is older ISO imported on vSphere LifeCycle Manager on vSphere UI.
On vSphere UI -> LifeCycle Manager -> Imported ISOs
During ESXi upgrade, in cleanup stage, there is a code which misses to cleanup the ISO for the last host (example: old 7.0.2 ISO).
The ISO which remains gets cleaned up with next ESXi upgrade using VUM which uses same ISO (example: Old 7.0.2 ISO).
But, Current error is VUM restricting to import duplicate ISOs during 7.0.3 upgrades. If VUM treats the old remnant ISO as duplicate of existing ISO during ISO import, VCF LCM upgrade fails at ESX_UPGRADE_VUM_STAGE_REGISTER_UPLOADED_FILES stage.
The issue has been fixed in LCM in VCF version 4.4.
To workaround the issue the ISOs that are listed under the below tab must be deleted:
On vSphere UI -> LifeCycle Manager -> Imported ISOs.