Large Calc File Crashes

I just upgraded to LibreOffice 5.1.5.2 and the previous indexing problem in Writer seems to have been resolved. But the large Calc files are still crashing when I attempt to save them. When I save them the dialog box states that “Calc is not responding” and then Win 10 looks for a resolution, it cannot find one and the program closes. In earlier versions of Calc (4.4 - 4.7) I will get the dialog that “Calc is not responding,” but the program will continue working until the Calc file is saved which may take almost a minute to complete. These same files can be opened and saved in Excel 13 and my earlier Lotus 123 programs (XP-Pro 3) without a hitch. Is there any way to resolve this problem so that the Calc software can save large files? Thank you.