Found this online. Have not tried it myself sorry.
Download the install/upgrade logs from the Cisco Unified Real-Time Monitoring Tool (RTMT), and gather the system-history.log.
or
Enter the file view install system-history.log command on the command-line interface (CLI).
Examine each instance of root: Boot, and confirm that each instance is preceded by one of these lines:
root: Restart
root: Shutdown
root: Install
root: Upgrade
If a boot instance is not proceeded by a Restart, Shutdown, Install, or Upgrade, there was likely an unclean shutdown.
This is an example of an unclean shutdown:
08/14/2012 13:36:09 | root: Boot 9.0.1.10000-37 Start
08/14/2012 17:28:25 | root: Boot 9.0.1.10000-37 Start