Microsoft Exchange Information Store service not starting after a reboot on servers running KES.
This is caused by the following registry key
and its value "Enabled" set to 1.
It prevents store from mounting correctly. This issue occurs only on servers where the AVG Email scanner for Exchange component is not installed, but was installed in the past. Currently there is a issue with AVG setup and it does not delete the registry key after uninstallation of the Email scanner for Exchange component.
Exchange servers with mailbox protection installed and active are not affected.
The solution is to open regedit and simply delete the whole "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\VirusScan" registry key. It is not enough to set the "Enabled" value to 0, as it may later be set back to 1.
This solution should be applied only on servers without Exchange mailbox protection enabled. To check this, go to the Security > Exchange Status function. If mailbox protection is enabled, the key should be present and "Enabled" item should be set to 1. It tells Exchange that VirusScan component is present and to check emails for viruses with AVG.
A registry key can be removed using a Kaseya Agent Procedure with a "Delete Registry Key" step.