PSpice_TI does not recognise it's .out.1 file

I have just installed PSpice_TI (v 17.4 on Win10 Pro) and created a simple switch mode current source project (SMCC). I set up the simulation, ran it and it failed to converge at many points. Of interest here though, on closing the project then restarting, an attempt at running the simulation again resulted in error ORPROBE-3074. It failed to read "SMCC.out.1" - a file it had previously created.

Has anyone seen this who can shed some light on the problem?