Hi,
it is very similar to your problem, considering that in this article we are talking about 2 TB. It is worth trying the proposed workaround
VMware vCenter Converter Standalone 6.2.0.1 Release Notes
Conversion job with no volume selected for shrinking fails with the following error message: 'An error occurred during the conversion: 'Block level cloning does not support shrinking volumes'
Converting a Windows source that has an LDM volume that is larger than 2 TB and the first disk of the volume is an MBR disk fails with the following error message: 'An error occurred during the conversion: 'Block level cloning does not support shrinking volumes'. Converter attempts to create an MBR disk larger than 2 TB on the destination but the limit of MBR disks is 2 TB.
The error does not occur on LDM volumes with a GPT first disk, because the destination disk type supports sizes larger than 2 TB.
Workaround: Convert the LDM volume at file level. Trigger the file-level cloning by shrinking volume size.
VMware vCenter Converter Standalone 6.2.0.1 Release Notes

ARomeo