PR Summary

AMSI is not getting uninitialized when a PowerShell shell window is closed by clicking the 'close' button instead of typing 'exit' at the command line, because the final runspace is not being closed. There is an assert checking for AMSI uninitialized during a CLR process exit, and it fires every time the window is closed via the close button. This fix removes the assert and replaces it with a check and call to uninitialize AMSI.

PR Context

The assert is very annoying and does nothing useful.

PR Checklist

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