.NET Tools Stop Working When You Upgrade .NET

Overview ☀ I was doing some housekeeping on seedfolder , a small .NET global tool I maintain that creates a project folder and fills it with sensible dotfiles. It targets net8.0 , net9.0 and net10.0 . .NET 8 and .NET 9 both reach end of support on 10 November 2026, so the plan was simple. Wait for November, drop both, ship a .NET 10 only version. Then I asked myself a question I could not answer…