The game window did't open while Java was running. I changed Deaths from 30 to 29 and the client could start. Deaths.dat contained 30 deaths but two same deaths connected without a seperator. The extra death was attributed to DeathFinder.
Minecraft 1.20, Fabric loader 0.14.21, Fabric api 0.83.0, Owo lib 0.11.0, Deathlog 0.3.2, DeathFinder 7.0.0.

This issue has nowhere enough information for me to do anything with it.

• First of all, always send your latest.log file from when the problem occured
• Then, when exactly did this happen? What did you do to trigger it - that is to say, how could I reproduce it?
• What do you mean by "without a separator"? If there's a defect in the database, please describe it more accurately - ideally with an example

Here is latest.log from when I reproduced the problem.
latest.log

And my deaths.dat, where the separator between the last two same (inexact) deaths is missing.
deaths.dat.zip

This happens when I launch Minecraft with mentioned Fabric, Owo lib, Deathlog, and death.dat which contains inconsistent Deaths and logged deaths (Like the uploaded one, also reproduced by removing some deaths from a normal deaths.dat).

The real question here though is how this even happened in the first place - what corrupted your database? I've never heard of this happening before and the circumstances are important since this problem would never even surface otherwise

Install Deathfinder (7.0.0 with ForgeConfigAPIPort 7.0.0 and PuzzlesLib 7.0.9), then new deaths are always duplicated, while a separator is occasionally missing. I can't reliably reproduce the missing separator. latest.log and deaths.dat from when the problem occurred once:
latest.log
deaths.dat.zip
There have been some related issues with Deathfinder, so my focus has been on dealing with the corrupt database.