I recieved some parts catalogs from a supplier in xlsx format, most I have been able to open with no problem, but a couple of them will open ok, but once you start scrolling up or down LO will freeze and eventually have to be shut down. I was on 5.2 LO and tried upgrading to 126.96.36.199 and it made no difference. The files are 5897 kb and 3112 kb, I tried converting one to .ods but that file also freezes after scrolling a bit. I also had the supplier resend the files but they are still the same issue. Win 7 OS.
Have the files a lot of images?
I would suggest two options to try:
a) use Apache OpenOffice rather than LibreOffice. AOO is much more stable. However, you won’t be able to save to XLSX.
b) try converting the files to ODS using ODF Converter.
Or ask the supplier to send you XLS files, not XLSX.
You probably need to expand the memory settings. Tools > Options > LibreOffice > Memory. This is especially important when using larger spreadsheets with a number of images. The standard settings are for the smaller files used by most users.