I just ran into what appears to be the same problem in uploading files to the Content Library, in my case vSphere 6.5. After some testing I discovered it seems to be dependent on the file size.
Anything over 4GB fails after transferring that amount, resulting in deletion of what was transferred. Files <4GB (e.g. a RHEL 7.3 install ISO) succeed, but Windows Server 2012 R2 ISO (4.x GB) or Windows Server 2016 (5.x GB) fail after transferring 4GB. This is true for ISO images and also for OVF files. The failures were accompanied by the same General System Error that you observed,
I have tried this in two different vCenter servers on different platforms, both with the same result. But surprisingly I can't find any reports of this in the knowledge base or via Google.
Did you ever resolve this problem.
Same issue with 6.5 larger iso files + 4GB cannot be uploaded