Recently we wanted to remove the Community Portal Solution from one of our Development instances.
Here, the solutions admin page doesn’t give the option of deleting or removing it.
To remove it, we need to uninstall all the solutions installed by the Dynamics 365 Portals – Community Portal.
Back in Dynamics 365 we can see so many solutions installed as part of community portal.
Here we need to remove the solutions in the reverse order of their installation. This information can be found in the solution entity within Dynamics 365 CE.
Thanks to this helpful post by Jon Birnbaum
Also, as soon as we start deleting the solutions, we’d get the Install option back again within the Solutions admin page for that instance.
Hope it helps..