Quick clarification: so both Workstation and Virtual Box can be installed at the same time on the same box, as long as they don't have to run at the same time?
Not working on a Win7 host !!
Since we have installed VMware Workstation pro 15 on our Win7 host, the Virtualbox (6.0.4) guests have their internet connection disconnected/reconnected every few seconds.
(Not running Virtualbox and VMware at the same time.)
After uninstalling VMware Workstation, the Virtualbox guests work fine again.
On a Win10 host both work fine so far.