'Project not defined' errors after updating to 15.77.6.7

Thank you, that is the likely culprit. We were running fine under TestComplete version 15.76, so have rolled back to that version for the time being while we figure out what we need to change to accommodate the Python runtime changes.

Again, nothing in our project changed between Friday and today, the sole change on any machine that had been running successfully on Friday was an update from 15.76 to this 15.77 version. A rollback has confirmed that is the cause of the change, as we are running fine again now under the prior version, so will now look into the Python support change(s).