I'm currently having problems getting the Exercise VM running correctly on my system. First system specs:
HOST: MacBook Pro, macOS High Sierra 10.13.2, 16GiB memory, a lot of disk space
VM Software: VirtualBox 5.1.30
I'm able to import the SSA on Pega 7.1.6 VM and start it up. I did make sure the network was enabled before I started. The first time, Ubuntu 12 starts up with "Trying to configure the network". Eventually, I get the console with the message to attempt to login to "http://:9080". Obviously that's not going to work.
I shut it down, head to the network settings for the image and change from Bridged Adapter to NAT. This time, it starts right up, gives me a 10.0.2.15:9080. address. This is great! But I use my HOST browser (Firefox 57.0.3) to try and connect to it and fail.
I then look at the Advanced section of the Network settings and change the Adapter type from PCnet-PCI II to Intel PRO/1000 MT Desktop. I leave it set as NAT. It still fails at the browser.
With the Intel PRO... still selected, I switch back to Bridged Adapter and get the "http://:9080" again. Also, with Bridged Adapter, I tried with Promiscuous Mode as Deny (default) and with "Allow VMs".
I have had this happen on a number of VMs and was able to solve this issue when using VirtualBox by changing the network configuration, Adapter 1, to a "Host-only Adapter". The downside to this change is that the VM does not have access to the internet which you may or may not care about.
Now, if you add a second (NAT) adapter and the networking config files are updated on the VM OS to support the second adapter will give the VM access to the internet. While probably not the only way to resolve this issue, this has been a very reliable method of configuring a number of the VMs so that I can work with them.
The synopsis was that a Windows upgrade somehow mucked up the VirtualBox Network Configurations such that I no longer had a Bridged Adapter available. So solution was simple enough - uninstall VirtualBox (it doesn't delete the VM, don't worry) then reinstall VirtualBox by right clicking and selecting Run as Administrator. Went back into Network Settings on the VM and was able to select a Bridged Adapter as I had before.