Why does sourcetree app keep crashing?

[Sam Tex]

I downloaded v3.4.3 from the website, but can't get it to work.  Seeing this error in the windows event log

Application: SourceTree.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.ComponentModel.Win32Exception
at System.Diagnostics.ProcessManager.OpenProcess(Int32, Int32, Boolean)
at System.Diagnostics.Process.GetProcessHandle(Int32, Boolean)
at System.Diagnostics.Process.Kill()
at SourceTree.Security.PageantSshKeyAgent.Kill()
at SourceTree.Security.PageantSshKeyAgent.Launch(Boolean, System.String)
at SourceTree.Security.DefaultSshKeyManager.LaunchSshAgent(Boolean, System.String)
at SourceTree.Security.DefaultSshKeyManager.LaunchSshAgent(Boolean)
at SourceTree.AppRoot.DoStartupTasksAfterFirstWindowDisplayed()
at SourceTree.MainWindow.OnContentRendered(System.EventArgs)
at System.Windows.Window.<PostContentRendered>b__202_0(System.Object)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate, System.Object, Int32)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(System.Object, System.Delegate, System.Object, Int32, System.Delegate)
at System.Windows.Threading.DispatcherOperation.InvokeImpl()
at MS.Internal.CulturePreservingExecutionContext.CallbackWrapper(System.Object)
at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
at MS.Internal.CulturePreservingExecutionContext.Run(MS.Internal.CulturePreservingExecutionContext, System.Threading.ContextCallback, System.Object)
at System.Windows.Threading.DispatcherOperation.Invoke()
at System.Windows.Threading.Dispatcher.ProcessQueue()
at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr, Int32, IntPtr, IntPtr, Boolean ByRef)
at MS.Win32.HwndWrapper.WndProc(IntPtr, Int32, IntPtr, IntPtr, Boolean ByRef)
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(System.Object)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(System.Delegate, System.Object, Int32)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(System.Object, System.Delegate, System.Object, Int32, System.Delegate)
at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(System.Windows.Threading.DispatcherPriority, System.TimeSpan, System.Delegate, System.Object, Int32)
at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr, Int32, IntPtr, IntPtr)
at MS.Win32.UnsafeNativeMethods.DispatchMessage(System.Windows.Interop.MSG ByRef)
at System.Windows.Threading.Dispatcher.PushFrameImpl(System.Windows.Threading.DispatcherFrame)
at System.Windows.Application.RunDispatcher(System.Object)
at System.Windows.Application.RunInternal(System.Windows.Window)
at SourceTree.App.Main()

[kloudmm]

I had exactly the same issue. In my case, I was logged in with two profiles on one machine, and that meant launching SourceTree the current profile couldn't kill `PuTTY SSH authentication agent`. I opened Task Manager and manually killed it, and that allowed SourceTree to start again.