I have an original, NIB Version of BOS Operation Barbarossa, that is intended to be an Add-on module for IL-2, or Forgotten Battles. Bought it a long time ago, and just re-discovered it. I have installed a playable version of IL-2. When I try to install my BOS OB, the message appears that "Additional Permissions Required", and nothing happens thereafter. Tried installing BOS OB module as Administrator, but no joy.

ETA, misidentified the add-on module. Correct title is Operation Barbarossa. Sorry.

I should add that I have a fully updated version of IL 1946. I wonder if the content in OB is included in 1946.

Any suggestions?

You'd probably need to download the BoS installer and then make a new account and input the cd key into your account.

If that doesnt work contact their support. Having a boxed version of BoS means that what is on the disc in no longer compatible with their account system and launcher.

https://il2sturmovik.com/account/registration/

Updated original post, so please re-read. sorry for the confusion on my part. Have signed-up at IL-2 site linked above, and awaiting confirmation email. thanks for the suggestion!

Seems to be third-party add-on missions for IL-2 / IL-2 FB, from 2003. Link

No idea if it will work with '46, but as it is third-party, I doubt that the content is included there. You might do better to ask in the IL-2/FB/'46 subforum , or maybe at 1C .