Bought and installed Bitdefender Internet Security 2017 on my Windows 10 Pro Insider Preview.
It caused an immediate slow down on opening any browser, to the point where they would time out.
I uninstalled, reinstalled a number of times, even Reset the Windows.
I posted a topic on the Bitdefender Forum and was answered rather short,
Bitdefender supports only the live version of the Windows operating system.
Insider builds are not supported.
I asked about a refund and this was the answer:
Please contact our support at firstname.lastname@example.org for more information regarding the refund policy.
The product supports all live versions, the insider is considered BETA, a unfinished product that is subjective to changes and glitches that don't usually make it to live version.
Product is really great and have been using it for years. Did not expect this type of answer.