Event ID - 300

Event Id300
SourceNTDS ISAM
DescriptionNTDS (244) The database engine is initiating recovery steps.
Event InformationThis event will be logged in a Domain Controller after an improper shutdown. This is an informational which indicates recovery process has started on NTDS.DIT.

If you are facing any serious problem like server hanging with error message "The Active Directory is rebuilding indices. Please wait", log in safe mode and run chkdsk /f on boot disk.
If the above given solution not working for you, it may need to replicate the data from other DC after an fresh installation.
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