SpiderDestroyer, your idea to use a spreadsheet as a backup source of data seems like an excellent idea. GoodGoomba, although my attempt to search the lss file for the split data failed, I thank you for the advice for how to make new category data without ruining other category data. When I was saving the old category data, I must have forgotten to close the splits. Overall, thank you to everyone who replied on this forum.

No, I do not have a video. All runs I have done were not recorded, though I was planning to record a speedrun on the day. Thank you for taking your time to help.

When I was trying to create new category splits on Livesplit, The data from the other category mysteriously disappeared. I tried reopening the data through the Livesplit menu (the one where you edit the splits, layout, etc) but an error occurred meaning I could not open the splits (although the layout had no issues with opening). If I don't find a way to reopen the splits file, I will lose my PB, as I don't yet have a run on the leaderboards. If anyone has an explanation for how this could have happened, a solution to find the lost files or advice for how to create new category splits without losing other splits data, I would really appreciate it if you replies on this forum.

Thank you for your attention to this forum.