She uninstalled Converter completely from the source machine (cleanup with Converter standalone clean-up utility ), deleted leftover VMware folders from ProgramData and AppData\Local , then reinstalled. Still broken.
She launched VMware vCenter Converter Standalone 6.2, clicked "Convert Machine," entered the source credentials, and hit next. The pre-check screen looked good—enough disk space, network reachable, agent uploaded. Then she clicked "Finish."
A red error bubble popped up: "Unable to start the change tracking driver."
She opened gpedit.msc and checked: System > Device Installation > Specify digital signature verification for device drivers. It was set to "Block." Even test-signed drivers were rejected. She uninstalled Converter completely from the source machine
She checked if the driver was even present. On the source machine, she opened C:\Windows\System32\drivers and looked for vmware-ctk.sys . Nothing. That meant Converter never installed it properly—or the OS blocked it.
Scrolling near the failure timestamp, she found the clue:
She closed her laptop, leaned back, and stared at the ceiling. She checked if the driver was even present
She disabled the AV real-time scanner temporarily. No change.
She tried the easy fix first: reboot the source server. The app team had said "no reboots until Q4," but Sarah had learned that "critical" sometimes meant "we forgot the admin password." She rebooted anyway.
This time, the driver installed. The progress bar jumped from 5% to 15%. stale driver remnants
She had done this a hundred times.
She changed it to "Warn" (temporarily), ran gpupdate /force , rebooted again, and started the conversion.
Bingo. The server had Hyper-V role installed (even though no VMs were running) and Device Guard enabled via group policy. Hyper-V and VMware’s change tracking driver cannot coexist—they fight for the same virtualization primitives.
Sarah remembered something from a deep-dive blog she’d read last year: Change Tracking driver issues are almost always about antivirus, stale driver remnants, or missing certificates.