Can't deploy to Android: HRESULT E_FAIL has been returned from a call to a COM component

I can no longer deploy to Android, and I'm not entirely sure what triggered it.

I can build for Android, and I can build & deploy for iOS and UWP.

I get the following deployment error (and stacktrace):

Xamarin.VisualStudio.ProgressReport|Error|0|System.Runtime.InteropServices.COMException (0x80004005): Error HRESULT E_FAIL has been returned from a call to a COM component.
   at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo)
   at Microsoft.VisualStudio.Package.Automation.OAProject.get_UniqueName()
   at Xamarin.VisualStudio.ProjectSystem.SolutionEvents.<>c__DisplayClass85_1.<GetStartupProjects>b__1(String name) in C:\d\lanes\4033\73f58d6d\source\xamarinvs\src\Core\VisualStudio\ProjectSystem\SolutionEvents.cs:line 311
   at System.Linq.Enumerable.Any[TSource](IEnumerable`1 source, Func`2 predicate)
   at Xamarin.VisualStudio.ProjectSystem.SolutionEvents.<>c__DisplayClass85_0.<GetStartupProjects>b__0(Project project) in C:\d\lanes\4033\73f58d6d\source\xamarinvs\src\Core\VisualStudio\ProjectSystem\SolutionEvents.cs:line 311
   at System.Linq.Enumerable.WhereArrayIterator`1.MoveNext()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at Xamarin.VisualStudio.ProjectSystem.SolutionEvents.GetStartupProjects() in C:\d\lanes\4033\73f58d6d\source\xamarinvs\src\Core\VisualStudio\ProjectSystem\SolutionEvents.cs:line 309
   at Xamarin.VisualStudio.ProjectSystem.SolutionState.get_StartupProjects() in C:\d\lanes\4033\73f58d6d\source\xamarinvs\src\Core\VisualStudio\ProjectSystem\SolutionState.cs:line 53
   at Xamarin.VisualStudio.Android.CommandHandlers.DeployCommandHandler.MoreThanOneProjectHasSameDevice(ISolutionState solutionState, DeployCommand command) in C:\d\lanes\4033\73f58d6d\source\xamarinvs\src\Core\VisualStudio.Android\CommandHandlers\DeployCommandHandler.cs:line 86
   at Xamarin.VisualStudio.Android.CommandHandlers.DeployCommandHandler.CanExecute(DeployCommand command, IProgressReport progress) in C:\d\lanes\4033\73f58d6d\source\xamarinvs\src\Core\VisualStudio.Android\CommandHandlers\DeployCommandHandler.cs:line 63
   at Xamarin.VisualStudio.Commands.CommandHandlerBase`2.Execute(TCommand command, CancellationToken cancellationToken) in C:\d\lanes\4033\73f58d6d\source\xamarinvs\src\Core\VisualStudio\Commands\CommandHandlerBase.cs:line 132

...

...As an afterthought, could this have anything to do with the recent Xamarin update? I will try and do a rollback tomorrow if no body knows a solution.