I just spent some time troubleshooting a parsing issue trying to import roms from a network connected drive. In the end I found that selecting all the roms as opposed to trying to import the folder they were in is what solved the issue. I think the fact that my nas drive is connected to a Mac may be what was causing the issue but I can't be sure. Like perhaps it was finding hidden files/folders that Mac OS generates and it choked on it. Or perhaps because LB uses .net runtime it gets confused with the folder structure. I turned on the debugger but it didn't generate a log file after the crash.
Note: This parsing error only occurred when trying to import large libraries. I had imported 15 other consoles using folders prior to this from the same drive just fine.
Anyhow, I wanted to leave this here as a potential fix for some people because I didn't find a solution here on the forums that matched what I did to fix it.