Omniscope is pretty good at opening common data files such as Excel (both .XLS and .XLSX) and Comma-Separated Values (.CSV), but not all files can be opened automatically.
Omniscope will always open Excel files from the File > Open menu, but it will expect a single header row in the first row of the worksheet from which to create names for all of the fields it creates. If the first row in your worksheet is blank, or contains data (rather than field names), then you can tell Omniscope this - simply tick the Customise data import behaviour box in the bottom right of the Open file dialogue. From the Customise data import window you can then specify the number of rows to ignore (if your worksheet contains blank rows, or comments etc.), or specify that your data doesn't contain a header row.
When opening CSV files Omniscope expects to find those files in Excel-compatible CSV format, with rows terminated by CR+LF character codes. Most softeare applications which provide CSV export facilities do prepare CSV files in this way, but if you struggle to open the file in Omniscope it is worth checking the export options in your external application to see if you can alter the settings. It is also worth noting that Omnniscope expects to find text values enclosed within quotation marks (") - it will read files in which the data is not enclosed, but any commas in the raw daat will force extra columns to be created; a common problem with some CSV export routines. If Omniscope fails to read your CSV file as you expect then it is worth trying to open the file within Excel and then saving it again (as CSV or XLS) - but watch out for Excel truncating the data if you have more than 65,000 rows (or 1,000,000 rows if using Excel 2007 onwards).
If you are struggling to open your file in Omniscope or Excel, then it is worth trying a text editor - explore search and replace options to create an Omniscope-readable verion - a favourite of mine for this task is the excellent (if rather basic) HiEditor, available free from WinAsm at www.winasm.net/hieditor-1016.html.
If you are still struggling to open your data file, then it's probably time to invoke your technical support option and contact Visokio...