Adprep was unable to check the forest update status. Status/Consequence Adprep queries the directory to see if the forest ...

Adprep was unable to check the forest update status.
[Status/Consequence]
Adprep queries the directory to see if the forest has already been prepared. If the information is unavailable or unknown, Adprep proceeds without attempting this operation. 
[User Action] 
Restart Adprep and check the ADPrep.log file. Verify in the log file that this forest has already been successfully prepared.