WTFast depends on Base Filtering Engine service. It is a system module and it must be running. Apparently, some users do not have it running because of system problems or viruses.
You can check Base Filtering Engine status.
Here are the steps:
1. Open Start Menu
2. Search services.msc and run it.
3. Locate the “Base Filtering Engine” service and confirm it is running.
(Please note, the name may depend on the Windows language).
4. If it is missing, you will need to correct the issue with the instructions in the following Microsoft article:
Then reinstall WTfast - if you still encounter the same error, please put in a support ticket so we can send you an additional file you will require.