Dear Allin, I think we still have some problems with the .xlsx files: Sometimes Gretl (version 1.9.7 / build date 2012-03-01 / Windows Vista) can't see the data structure. This is a intriguing issue because even when the spreadsheets are equal (at least visually) Gretl shows a different behavior. Please take a look at the Teste.xlsx file attached. In that file we have two sheets with the same information. With the command, open C:\Users\f1831737\Desktop\Teste.xlsx --rowoffset=8 --sheet="IBC-Br SA" Gretl doesn't define the data structure (time series). But with the command, open C:\Users\f1831737\Desktop\Teste.xlsx --rowoffset=8 --sheet="IBC-Br SA (2)" Gretl defines my data as a time series. If I try to open via the GUI I get the following message/results: <message> 'IBC-Br SA' -> worksheets/sheet1.xml Found 6 variables and 385 observations" </message> And Gretl can not see the correct data structure. The same command in the second sheet gives me: <message> 'IBC-Br SA' -> worksheets/sheet1.xml didn't get worksheet xmlParseFile falhou em xl\rId2 </message> And Gretl doesn't open the data. Allin, sorry for bugging you (and all the list members) again with this subject, but I think the easiness of the data opening is one of the most important features of Gretl and, because of that, it's very important maintain its correct functioning. -- Henrique Andrade