Using Linux Mint 17.3 (32 bit) and Libre Office 5 Calc my spreadsheet is now illegible. A grey box with Text Import appears. All my numbers appear as dark black diamonds. Recovery didn't work. Please help.

Using Linux Mint 17.3 (32 bit) and Libre Office 5 Calc my ods spreadsheet is now illegible. A grey box with Text Import appears. All my numbers appear as dark black diamonds. Recovery didn’t work. Please help. I changed language to English USA as requested but I had used these spreadsheets for years without a problem. The file was readable in both Windows 10 and Linux until 17.2.2017. Now not readable in either one.

Please try disabling Open G,L Menu/Tools/Options/LibreOffice/View