Hello @buff,
When you mentioned, "This is for a freeform project which was functioning before I performed an upgrade," could you please clarify what was upgraded?
In order to try a pinpoint if this solves the issue, could you perform the following tests?
-In the Debug Probes window, click Clean-up Debug and then click the Refresh button.
-Update the MCUXpresso Installer to the latest available version. You can follow the steps described in the Package and Component Status, Version, and Updates section.
-Reinstall the SEGGER J-Link Software Pack from the MCUXpresso Installer.
Also, could you please provide me which device are you currently using? Is one of our EVKs or is a custom board?
BR
Habib