Steps to reproduce:
1. I created an excel file and saved that to example.xml
2. then Opened that file in LO while keeping excel open
3. modify then tried to save file in LO
4. choose XML (instead of odf)
-> crash (log: http://pastebin.com/iyiSbTZa)
Tested with LO 188.8.131.52. Also the crash is reproducible.
Operating System: Mac OS X
Version: 184.108.40.206 release
Still reproducible with LO 220.127.116.11.
Works for me. Tested using Mac OSX 10.9 with LibreOffice Version: 18.104.22.168.alpha1+
Build ID: d93433ba1181f5d8f6ded0ed0c103df10ebb1f22
TinderBox: MacOSX-x86@49-TDF, Branch:master, Time: 2013-11-20_13:04:00