Hi,
The most common cause of this issue would be another dialog window opening up in the background. Due to WinForms/WPF interop issues, dialog windows sometimes appear underneath the regular VS window and are hence not visible. Please check the task list (Alt-Tab) and the VS icon in the Task Manager to see if there are any extra dialog windows (e.g. confirming some missing tools).
If it doesn’t help, please try updating to VisualGDB 5.5 Preview 3 and let us know the exact project type you are creating (Embedded/Linux/etc; CMake/MSBuild/GNU Make) and also whether the problem triggers for other project types. Also please share a screenshot and a call stack or the frozen VS instance once it freezes for about 1 minute or more.