Sorry to hear it, I can open Blackhole in FL Studio on Win10 here, so the issue may be with your configuration. Sometimes it can help to do an uninstall and fresh install. Please try the following:

1. Uninstall Blackhole: Control Panel -> Uninstall a program
2. Open FL Studio, and rescan all of your plugins. Then close FL Studio.
3. In iLok License Manager, deactivate the Blackhole license, then reactivate it again.
4. Reinstall Blackhole
5. Open FL Studio
6. Rescan your plugins if needed. You should make sure "Rescan previously verified plugins", and "Rescan plugins with errors" are selected under "Scan Options" before rescanning.

Let me know if you still experience problems.