Hi, OnderjMM,
We can rename only the long name by setting options.Names.FNameToBkLnOnly to 1. The options variable of the impasc X-Function is a tree to control the import options. It has a branch called Names to control target workbook naming and the node FNameToBkLnOnly is for specifying whether to rename only the workbook.
Please try the following script:
fname$=system.path.program$+"samples\signal processing\fftfilter1.dat";
impasc options.Names.FNameToBkLnOnly:=1;
Deanna
OriginLab Technical Services