I run Windows 10 gretl release 2026b.

I get the following when I try to open an existing gretl session. I have closed and opened it in the past, no problem. 

I looked at the path, after "...\Roaming\gretl\",  there does not appear to exist "...\.PWT_110_2TSF" at all so neither "...\.PWT_110_2TSF\pwt110.gdt".

It has happened also in the past with other sessions. Any advice as to what I could do to fix this?