Hi Umut,
That message indicates there is a problem in the formatting of the file. I assume that this is a SAM CSV file with solar resource data.
You could try running the Solar Resource File Checker macro (click
Macros under the Simulate button to see a list of macros) to see if it provides any more useful information.
Otherwise, open the file in a spreadsheet program or text editor and use the format descriptions in Help to try to find the problem:
samrepo.nrelcloud.org/help/weather_format.htm. For example, check the number of rows in the file: A file with one-minute data should have 8760 hours/year * 60 minutes/hour * 1 time step/minute = 525,600 time steps, plus 2 header rows and 1 column heading row.
You could also use the Solar Resource Interpolation macro to convert an hourly file to one-minute data to create an example of a one-minute data file that is correctly formatted, and then compare the resulting file with yours to see if you can find the problem that way.
If all of that fails, please attach a copy of your file and I will see if I can find the problem.
Best regards,
Paul.