[BetterRed]

Path is a system environment variable, no need to touch.

Follow these steps:

1. Winkey+R
2. type sysdm.cpl
3. click OK
4. System properties panel will pop
5. Click the Advanced Tab
6. Click the Environment Variables button
7. Click New button under the User variiable for xxxxxxxx
8. Enter CALIBRE_NO_DEFAULT_PROGRAMS in Variable name
9. Enter true in Variable value
10. Click OK
11. Click OK at bottom of panel
12. Click OK in System properties dialogue

Done

Did you run the calibre-debug --default-programs=unregister command, wont hurt to run it again.

Now trying double clicking an ePub in your file manager, should be okay, if not try a windows restart and try again, if not okay come back to us.

Wash your hands

BR