StarWind Software

Hi All,

I've been trying to convert VMs from vCenter to Proxmox but every time I try it fails with this error:
Facility ???ERROR: Proxmox::WrapperProxmox::WrapperProxmoxImpl::Connect: Failed to parse JSON response

Here's the entire log in case that's needed. Please let me know how I can get past this so I can use the product.

1/6 16:21:03.417 8c0 Facility ???INFO: CV2V_ConverterApp::InitInstance: SetDllDirectory: C:\Program Files\StarWind Software\StarWind V2V Converter\lib
1/6 16:21:03.417 8c0 Facility ???INFO: CV2V_ConverterApp::InitInstance: File Version: 9.0.1.848
1/6 16:21:03.417 8c0 Facility ???INFO: CV2V_ConverterApp::InitInstance: Load language IDR_XML_ENGLISH
1/6 16:21:03.417 8c0 Facility ???INFO: CV2V_ConverterApp::InitInstance: Set current language English
1/6 16:21:03.433 8c0 Facility ???INFO: CPS_V2V_Converter::CPS_V2V_Converter: Version MajorVersion 10, MinorVersion 0, BuildNumber 26200
1/6 16:21:03.451 8c0 Facility ???INFO: WrapperHyperV::WrapperHyperV: LoadLibrary C:\WINDOWS\system32\wbem\wmiutils.dll - 29d60000
1/6 16:21:03.451 8c0 Facility ???INFO: WrapperHyperV::WrapperHyperV: LoadLibrary C:\WINDOWS\system32\wbem\wmiutils.dll - 29d60000
1/6 16:21:07.294 8c0 Facility ???INFO: ICPPage::OnWizardNext: SetActivePage - eESXConnection
1/6 16:21:20.402 3970 Facility ???INFO: WrapperESXI::connect: m_url - *omitted*
1/6 16:21:21.317 3970 Facility ???INFO: WrapperESXI::connect: fullName - , key - 52e6a988-8fcd-af0b-623d-04d61887f452
1/6 16:21:21.319 3874 Facility ???INFO: VMConverter::ESXIConverter::Connection::<lambda_4eab79f5f0516eba86b7810fe0d8b684>::operator (): Worker thread started.
1/6 16:21:21.319 3970 Facility ???INFO: VMConverter::ESXIConverter::Connection: No_timeout ESX connection
1/6 16:21:21.321 8c0 Facility ???INFO: ICPPage::OnWizardNext: SetActivePage - eInputVM
1/6 16:21:47.849 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:21:47.849 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:21:47.849 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:21:47.849 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:21:47.849 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:21:47.849 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:21:47.849 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:21:47.849 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:21:47.849 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:21:47.849 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:21:47.849 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:21:56.199 8c0 Facility ???INFO: ICPPage::OnWizardNext: SetActivePage - eLocationTo
1/6 16:22:00.738 8c0 Facility ???INFO: ICPPage::OnWizardBack: SetActivePage - eInputVM
1/6 16:22:51.784 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:22:51.784 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:22:51.784 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:22:51.784 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:22:51.784 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:22:51.784 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:22:51.784 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:22:51.784 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:22:51.784 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:22:51.784 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:22:51.784 8c0 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 7.0.3
1/6 16:23:05.517 8c0 Facility ???INFO: ICPPage::OnWizardNext: SetActivePage - (null)
1/6 16:23:10.659 8c0 Facility ???INFO: CPPSynchronization::onNext: Synchronization for - [
1/6 16:23:10.659 8c0 Facility ???INFO: CPPSynchronization::onNext: Synchronization for - [
1/6 16:23:10.659 8c0 Facility ???INFO: CPPSynchronization::onNext: Synchronization for - [
1/6 16:23:10.659 8c0 Facility ???INFO: ICPPage::OnWizardNext: SetActivePage - eLocationTo
1/6 16:23:13.876 8c0 Facility ???INFO: ICPPage::OnWizardNext: SetActivePage - (null)
1/6 16:23:39.533 13e4 Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::Connect: Connect to Proxmox host
1/6 16:23:39.533 13e4 Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::GetHostVersion: Get proxmox host version info
1/6 16:23:46.543 13e4 Facility ???ERROR: Proxmox::WrapperProxmox::WrapperProxmoxImpl::Connect: Failed to parse JSON response
1/6 16:23:53.969 3874 Facility ???INFO: VMConverter::ESXIConverter::Connection::<lambda_4eab79f5f0516eba86b7810fe0d8b684>::operator (): Worker thread exiting.

I believe it's more related to Proxmox than StarWind V2V.
I think the easiest might be copying the VMDKs and deploying that VM in place.

yaroslav (staff) wrote: ↑

Wed Jan 07, 2026 8:18 am

I believe it's more related to Proxmox than StarWind V2V.
I think the easiest might be copying the VMDKs and deploying that VM in place.

I believe it's more related to StarWind V2V than Proxmox.
Can we please get some assistance troubleshooting this issue before immediately passing the buck off and telling us to "do it manually"?
After reading many forum posts here, it seems that's the go to reply for anything but the simplest of issues posted. Why is that? The whole point of ANYONE running this software is to prevent having to do it manually.

All I was trying to do was deliver the fastest solution so you don't wait for me to discuss things internally/check logs.
Could you please let me know the version of Proxmox you have?

I have this exact issue. I’ve tried with both a Proxmox 8.4 and 9.1 host, same issue, ‘failed to parse JSON response’. Works fine from an ESXi host a HyperV host. Might it be anything to do with having a specific version of JavaScript installed?

Thanks for your update. I will log an internal request to check.

Please try this one https://starwind.my.salesforce.com/sfc/ ... 1WvfQ3eHKE.

Installed the updated application, and it worked perfectly from ESXi to PVE 9.1. No issues logging into either the ESXi or PVE hosts.

Thank you so much!

Thanks for your feedback!

The download link seems to be no longer valid.
I'm still having this issue with 9.0.1.848:

6/8 14:18:19.343 7b1c Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::Connect: Connect to Proxmox host
6/8 14:18:19.343 7b1c Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::GetHostVersion: Get proxmox host version info
6/8 14:18:25.488 7b1c Facility ???ERROR: Proxmox::WrapperProxmox::WrapperProxmoxImpl::Connect: Failed to parse JSON response

Is the fix included in version 848?

Hi, try this one https://starwind.my.salesforce.com/sfc/ ... XlX0Tfgtsw.

Hi Yaroslav,

Thanks! That helps logging into Proxmox.
However after logging into the Proxmox cluster host, the list of Storage options and the list of Nodes are both empty.
When I try to continue the conversion, it fails with a "Not enough space" error, even though there is plenty space on some of the storage attached to this cluster.

For reference here's the log:

6/10 13:10:30.871 244 Facility ???INFO: VMConverter::ESXIConverter::Connection: No_timeout ESX connection
6/10 13:10:30.873 20a8 Facility ???INFO: ICPPage::OnWizardNext: SetActivePage - eInputVM
6/10 13:10:32.048 20a8 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 8.0.3
6/10 13:10:32.048 20a8 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 8.0.3
6/10 13:10:32.048 20a8 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 8.0.3
6/10 13:10:32.048 20a8 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 8.0.3
6/10 13:10:32.048 20a8 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 8.0.3
6/10 13:10:32.048 20a8 Facility ???INFO: VMConverter::ESXIConverter::GetHostListInfo: ESX version: 8.0.3
6/10 13:10:37.771 20a8 Facility ???INFO: ICPPage::OnWizardNext: SetActivePage - eLocationTo
6/10 13:10:41.280 20a8 Facility ???INFO: ICPPage::OnWizardNext: SetActivePage - (null)
6/10 13:10:54.927 2090 Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::Connect: Connect to Proxmox host
6/10 13:10:54.927 2090 Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::GetHostVersion: Get proxmox host version info
6/10 13:10:55.304 2090 Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::GetHostVersion: Get proxmox host version info
6/10 13:10:55.306 2090 Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::BuildVM: Get virtual machines lists
6/10 13:10:55.310 2090 Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::Connect: Successfully connected to proxmox host
6/10 13:10:55.310 20a8 Facility ???INFO: ICPPage::OnWizardNext: SetActivePage - eTypeP2V
6/10 13:11:36.959 20a8 Facility ???INFO: ICPPage::OnWizardNext: SetActivePage - eHYPERVConnectionTo
6/10 13:11:36.969 1094 Facility ???INFO: CPPConverting::Convert: InConvertType: 6, OutConvertType: 16
6/10 13:11:36.971 1094 Facility ???INFO: CPPConverting::Convert: Converting VM "254.029 IWS W2019" (1 of 1)
6/10 13:11:36.971 2118 Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::CreateVM: CreateVM attempt 1/10
6/10 13:11:36.971 2118 Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::CreateVM: Set disks
6/10 13:11:36.971 2118 Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::CreateVM: disk name scsi0, :79.000000,format=raw
6/10 13:11:36.971 2118 Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::CreateVM: disk name scsi1, :40.000000,format=raw
6/10 13:11:36.971 2118 Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::CreateVM: disk name scsi2, :59.000000,format=raw
6/10 13:11:36.971 2118 Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::isEnoughSpace: disk name disk size = 78.125000 Gb
6/10 13:11:36.971 2118 Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::isEnoughSpace: disk name disk size = 39.062500 Gb
6/10 13:11:36.971 2118 Facility ???INFO: Proxmox::WrapperProxmox::WrapperProxmoxImpl::isEnoughSpace: disk name disk size = 58.593750 Gb
6/10 13:11:36.971 2118 Facility ???ERROR: Proxmox::WrapperProxmox::WrapperProxmoxImpl::CreateVM: Not enough space
6/10 13:11:36.971 1094 Facility ???ERROR: CPPConverting::Convert: FAILED

FYI: I'm running the latest Proxmox VE version: 9.2.3

Thanks for your update!
Please tell me more about this conversion
- What you are converting: Host OS and version.
- Are you connecting to vCenter or ESXI?
- Scenario (v2v/P2V)
- Disk type Zeroed/Thin
Try converting individual disks; see if it allows you to select the destination, or try the Proxmox converter https://www.nakivo.com/blog/migrate-vmware-to-proxmox/.
As a workaround, you can try converting to an intermediate host.

We are migrating from VMware vSphere/ESXi to Proxmox.
At the moment I connect to vCenter, but I can try connecting directly to an ESXi host too.

The VMs are thin-provisioned on the vSphere side, and will be thin-provisioned on the Proxmox side too.
I'll give it a go with the individual disks.

I was not aware of that other conversion tool, thanks so much for that link.