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vCenter Converter Standalone 6.0.0 build-2716716, running on WinXP SP3 host. When attempting to reconfigure the guest OS, either during conversion of of a Virtual PC VM -> Workstation (or a subsequent configure-only run of the converted VM), I received:
Error: An error occurred during reconfiguration.
and
FAILED: Unable to create '\\.\vstor2-mntapi20-shared-F72AF82A007E0000000000001A000000\$Reconfig$'.
Rebooting and closing all non-essential apps, then rerunning the configure-only job resulted in success.