GPG4WIN (useful for ISE logs)
Cisco ISE crash and error logs are often encrypted before they are saved and you as the administrator are usually the one setting the password needed to decrypt the content. In most cases you are supposed to hand the logs over to the Cisco TAC for advanced troubleshooting, but you can use this tool to take a look at the logs for yourself.
Download the GNU Privacy Guard for Windows (Gpg4win) and use the Kleopatra module to extract your log files.
You can you this tool to read fail-logs from the ISE Upgrade Readiness Tool (URT). Look for the file dbupgrade-data-global-xxxx-xxxx.log inside \urt_logs\opt\CSCOcpm\logs\