Vagrant Stopped Working, Says VirtualBox Version is Not Supported

Question

I have Vagrant 1.6.3 and VirtualBox 4.3.12 on Windows 8.1 Pro(64 bits). Vagrant was working fine till yesterday.

Suddenly, it started giving this error on vagrant up (in powershell):

The provider 'virtualbox' that was requested to back the machine
'default' is reporting that it isn't usable on this system. The
reason is shown below:

Vagrant has detected that you have a version of VirtualBox installed
that is not supported. Please install one of the supported versions
listed below to use Vagrant:

4.0, 4.1, 4.2, 4.3

I have tried following:

1. Uninstall both Vagrant and VirtualBox (5-6 times) and reinstall. I rebooted after every install/uninstall.
2. Tried different (latest as well as older) versions of both Vagrant and VirtualBox. I have tried Vagrant 1.6.3 and Vagrant 1.6.5, VirtualBox 4.3.16, 4.3.12, 4.3.10.
3. Disabling anti virus and firewall. (Both Vagrant and VirtualBox are added to exclusion list)
4. Checking that VirtualBox is added in Environment Path.

Anything that I am missing? I tried searching and only two relevant links I found were: Vagrant has detected that you have a version of VirtualBox installed that is not supported (does not work), Vagrant has detected that the VirtualBox installed is not supported (fixed in Vagrant 1.5)

Any should I do now?

Answer 1

The problem was with Firewall. I recently switched to Comodo firewall and it was causing the issue.