this software is able to split all the backuped messages into separate conversation between you and the other only.
1- Download your archive ZIP (backup) from facebook and extract it
- Here how to get it : https://www.facebook.com/help/131112897028467/
2- Run FBMsgsSplitter.exe and Click on "Open messages.htm"
3- Locate the file, should be in the extracted archive folder \html
eg. \facebook-yourfbname\html\messages.htm
4- Click on split messages and wait few seconds.
5- A message box...