CbB installation woes on Win 10 (Due to BitDefender AV) [SOLVED by Firewall Rules]

I'm a SPlat user who has been dual booting Windows 7 and 10 for a long time (each has their own separate SSD and my BIOS lets me choose which to boot). I use Win 7 99% of the time and log on occasionally to Win 10 to do updates etc. I knew that one day I would be reluctantly forced to migrate to Win 10 but for various reasons have resisted, until now. 
 
Booted into Win 10 this morning - it did an update and....totally screwed up my Win 7 SSD. It won't boot, it won't repair (tried the Win 7 boot DVD and SpotMau Bootsuite). 
 
So I decided to cut my losses and spend the time bringing my Win 10 up to date. This included installing CbB which until now has been running nicely on Win 7 alongside SPlat. When I install BA on Win 10 and choose the install (CbB) option it opens a web browser (the donation page) and promptly shuts itself down so it doesn't get as far as installing CbB. I found the CbB executable from my Win 7 install and installed it that way and of course it is now stuck in demo mode (I have seen the other threads). However I cannot see a workable way to install it in Win 10 as BA shuts itself down when I tell it to install CbB. I have BitDefender AV and Malwarebytes (with the same settings as my Win 7 install). 
 
Any thoughts on why BA is shutting itself down and how to stop it doing this?
 
Thanks
ZT

CbB uninstall will probably remove all the shared files used by both CbB and SONAR.
 

If the shared files are removed all you need to do to get them back is re-run the SONAR installer or rollback and roll forward using the Command Center. Assuming you don't reinstall CbB first.
 

ionecake
Multi-booting can be problematic without a really good strategy to protect the boot drives/partitions from each other. What I've found effective is to use a third-party boot manager like TeraByte Unlimited's BootIt Bate Metal, OR, I use the BIOS, but I make sure to *disable* the alternate SATA port where the other boot drive is, making it impossible to be tampered with by any other boot drive/partition. Both of these approaches have worked on *many* workstations over the years.
 
As for antivirus, I've had some decent success with ESET, as it has never interfered with DAW installations, and it has a low CPU impact. I've tried about 5 other security suites, and always come back to ESET for the DAW.
 
Good luck!

Thanks, I should definitely have protected the Win 7 drive from before doing the Win 10 update. It had never happened before which lulled me into a false sense of security. Simply unplugging the Win 7 drive would have prevented the problem. I am still not quite there with the Win 7 installation (Winload.exe error). Annoyingly I can no longer access the drive from Win 10 (Access Denied) so I have to recover any files on it when booted into a recovery environment. Fortunately I have most data including Sonar Projects on other internal drives (and backed up to external drives) so it's really just programs/settings/bookmarks/Fences configs etc that I need to re-create. 
 
I switched to BitDefender from Kaspersky due to worries about the latter after reading good reviews for the former.
It seems a bit more "in your face" than Kaspersky and has also thrown up a few false positives that didn't bother Kaspersky. I have also switched off the app blocker as it usually interferes with installations.

I managed to get CbB working by uninstalling the demo mode version then re-installing from within BA (worked fine this time with BA allowed in the Firewall rules). SPlat still seems OK after doing that fingers crossed.
 
Just need to sort out:
 
Kontakt - it is unable to find the libraries that were on my Win 7 SSD which I need to re-install elsewhere and Native Access is out of step with what I do have installed. Probably just need to re-install the latter in NA on Win 10.
 
Steinberg - Cubase Elements 9.5, Halion Sonic 3 and Halion Symphonic Orchestra aren't showing in my Soft Elicenser and it is showing as deprecated on MySteinberg website. The Steinberg support ticket has now been unanswered for 2 days. 

Thanks karhide, yes I'm hopefully getting there :)