First of all, thanks for the reply.
Unluckily also the test file attached can't be read by flowheater.
Anyway, I succesfully managed to read the file after changing the "standard and format" option, under Control Panel-->Regional and Language Option, from
Italian to
English UK.
Basically, my version of Excel is in English Language, and so, I've had to change the regional and language option of the PC to English, in order to make Flowheater able to read the Excel file (in other words, the "language" selected under the Regional and Language Option must be the same of the Excel version installed).
Obviously, this is a workaround 'cause I'd like to use my preferred Language option, instead of changing it.
Hope it helps to find a solution...
thank you
Best regards
