Had been plagued again recently by this issue, happened twice in a row now. Opened PRT, strategies loaded, made a change to one of them and by the time I wanted to execute the change. The Run Backtest button didn’t work. Could still edit code but couldn’t run the backtest or close PRT with the ‘x’. Closed PRT via Task manager and restarted usually this allows me to continue working for at least a couple more hours, but not this time. Exactly the same thing happened twice in a row.