Welcome to the Cryptomator Community 
crashes are not written to the regular log, but to a special crash log. To ensure the crash log is created, edit with admin permissions the file C:\Program Files\Cryptomator\app\Cryptomator.cfg and as first line in the JavaOptions section, add the following line:
java-options=-XX:ErrorFile=C:\Users\[YOUR USERNAME]\cryptomator_crash.log
where [YOUR USERNAME] must be replaced with the logged in accountname.
Afterwards, restart the Cryptomator app and trigger the crash. Once done, the crash log can be found at the above specified path. You can send us the regular and the crash log via mail at support@cryptomator.org .