If you've followed all the steps in the How to re-enable the Outlook Plug-in if it gets disabled and Outlook continues to get disabled, or doesn't re-enable, please follow these steps:
- Quit Outlook and uninstall the “Biba for Outlook” plugin from Control Panel(Add/Remove Programs, or Programs and Features depending on your Windows version).
- Open the registry (run regedit.exe)
- Navigate to the key HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Resiliency (You may need to change 16.0 to another number based on your version of Office. 15.0 for Outlook 2013, 14.0 for Outlook 2010, 13.0 for Outlook 2007, etc.)
- Remove the REG_BINARY keys found in DisabledItems and CrashingAddinList
- Navigate to HKEY_CURRENT_USER\Software\Microsoft\Office\Outlook\Addins
- Remove the BibaOutlookPlugin key
- Reinstall the Biba plugin for Outlook and then open Outlook and see if it is enabled on the calendar tab.