I don't think this popular problem is related to the vDisks. First of all, I suggest removing your source vNIC before executing the convert operation. However, I don't have experience with converting failure because of vNIC, because finally, you may need to remove the old hidden vNIC and add another one. But if you check this procedure's related logs for more details, maybe we can help you better.
i will try removing the vNIC
I removed the vNIC, but it still has the issue. I read somewhere that it may be a hardware incompatibility. The VM was made with workstation Pro 15. and my VSpere is 6.0
I couldn't find any official compatibility link, however you can try this operation with an earlier version like VMware Workstation 12. ( I'm sure it's compatible with ESXi 6.0)
I cloned the VM and using the hardware compability option. I did not get the same error. Invalid configuration for device line 25
I received a new error
Invalid configuration for device '0'
I removed the vNIC, but still received the error.
The VM is windows 7 .
No I still cannot convert the VM after cloning with the hardware compatibility.
I have discovered VCenter stand alone Converter will not convert it. There is a hashing issue. Workstation uses SHA256 and ESX needs it to be hashed in SHA1
I have exported the VM to an OVF, however I get an configuration error with line '0'
I have removed the vNIC
Did you generate your OVF file via connecting to the ESXi host or via the vCenter management? If there is not-enabled Lockdown Mode settings for your ESXi host, please try it via ESXi directly and then give back the result.