Hello.
We have vSphere 6.7 u3
I opened this post because looks like i dont understand how should looks like update process for operating systems. Issue starting after some operations in catalog during OS update.
We have opened SR: 19080739611
The problem looks that.
We have now affected all Windows Server template. After some long troubleshooting what we have.
When client download VM to OVA by tenant portal and next try import to vCD process is hanging on 1%
on NFS we have VMDK capacity is 0:
After some time we have timeout... and task fails with specific description....
7 zip is not working to extract OVA (worked before we performed planned OS updates)
Working only WinRar. And after extracting OVA to 3 files and importing them by tenant or flex client is possible to import VM again.
Problem is not observed when we have a fresh template (created inside vCD). When we create some new VMs we can download and import OVA with success.(by tenant client)
The problem started after some time. Last time we observed this issue after Windows Server 2019 update. Maybe this is not related to the specific OS but some activity on vCD level.
The process which we performed during update ( i received this from our OS engineer)
## Update process:
1. Deployment vAPP from Catalog (in Public ORG for templates):.
2. Start VM with network ==> UPDATE OS ==> Stop VM
3. Add to Catalog (with overwrite option and with Customize Vm settings)
4. Deployment vAPP from Catalog (in Public ORG for templates):.
5. Remove network (ORG VDC Network) from vAPP and VM
6. Add to Catalog (with overwrite option and with Customize Vm settings)
Im not sure why we are twice time adding to Catalog... but this is normal operation in my opinion.
From GSS support we not received the good solution. Because "they don't know what we did exactly during this update process".... and suggest importing new VMs from vCenter...( maybe every month ? 
)
Problem not exist in Flex client... which will be not available in next vCD version...
What is strange OVA from tenant and flex client is different inside.... (exactly that same VM)
For importing those OVA to vSphere we have problems too... but for this, we have different workaround VMware Knowledge Base
For now,for vCD we have only workaround related to WinRar.
How looks like you update OS process ? in your environments?
Sebastian