Hello there,
This can happen if your PackageManagement module isn't up to date, VSCode picks up on that, displays a pop-up on the lower right of the screen asking if you want to update and doesn't consider Powershell started until it's dismissed.
Installing the latest version of package management and then restarting either the PowerShell session or VSCode resolved the issue for most of the users who faced the similar issues.
You also may need to make sure that you don't have this Session exited warning. If you do, click "Restart Current Session", then try pressing F5 again.
I hope this information helps. If you have any questions please let me know and I will be glad to help you out.
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