I have no clear idea about this situation but once ctk files are present locally - the question is how they arrive - through Converter's copy or from 3rd party software running locally?
Otherwise, if CBT is disabled, no ctk files should exist locally (must be confirmed with tests), and the pattern seems to be "*-ctk.vmdk", however is these files are transferred from Converter's copy and then if they can't be pushed back - check the file's rights with cacls command or via file-explorer, normally all files for one VM i.e. VMX, VMDK, NVRAM, etc, must be with same access rights.
HTH