The Exchange Information Store service does not start
This issue occurs when the virus-scanning entry remains in the registry after uninstalling the Bitdefender for Exchange. In order to solve this open the registry editor and browse to the key below:
On the right pane locate the "Enabled" value, double click it and set its "Value data" to 0.
You may find more information regarding this issue in this Microsoft KnowledgeBase article available here.