Calc taking too long to load Quickbooks export file

Using Ubuntu 16.04 running Libreoffice 5.3.3.2.

When i try to look at a sheet that contains export of quickbooks data saved on a Windows machine using excel, it takes a full minute or more to open the sheet and the screen dulls to a grey display and unable to do anything. The sheet itself has only 360 or so rows on 20 columns. Every time I switch back from another sheet back to the data export sheet the same problem occurs. Copied and pasted the data into another file and still get the problem. It seems a bit strange that it is having memory problems on a relatively small amount of data!

Any ideas how to fix?
Regards,
BB