libreoffice becomes unresponsive when I apply justified alignment to Default Style

I have applied CTRL+M (clear formatting) to a big document with about 147000 words. Now, when I try to change alignment to Justified in Default Style, the application becomes unresponsive. Tried it many times, it always behaves the same and I have to kill the application, and when I open it, the alignment is set to the former alignment that it had before my attempt. I came across several pages on LibreOffice documentation that suggested changing user profile if LO shows strange behavior. However, I do not think it is worth losing my templates and styles just to apply an alignment. Any suggestions?

system info:
LibreOffice 10(Build:2) on Fedora 24

A couple of thoughts. Is it possible that each line is its own paragraph? This happens frequently with copied pdf files. If so, it places a large burden on LO to convert all of them in any significant way. Shouldn’t be so, ideally, but that’s what I’ve found. If so, it might pay to remove extraneous linefeeds first.

IAC, one workaround might be to create a new style based on the style you’re using, then convert limited sections of the document successively to the new style. This would reduce the impact on LO’s resources.

Also, go to Options / Memory and increase the allotments to LO.