The Anti-Virus (Anti-Spam) module has been switched to limited scan mode [Kaspersky Security for Microsoft Exchange Server]

Version: Kaspersky Security for Exchange 9.5.10000.64, 9.6.96

Scenario

In Kaspersky Security 9.0 for Microsoft Exchange Servers  there's the following error event: "AM Error Kernel: The Anti-Virus (Anti-Spam) module has been switched to limited scan mode for next 30 minutes. Some objects may be skipped without being scanned."

The same error message appears on the KSE console:

Solution

Sometimes Exchange tries to give KSE more emails to check than KSE is able to to check. In order to prevent delays in mail delivery, the anti-virus or/and anti-spam engine switches to a special mode of operation called "Limited scan mode".

This mode lasts for 30 minutes. During this period, some emails may be skipped for checking.
The transition to normal mode is carried out automatically after the time specified above.
You can find out about this mode of operation in our Online Help:

https://support.kaspersky.com/KS4Exchange/9.6/en-US/28854.htm
https://support.kaspersky.com/KS4Exchange/9.6/en-US/99915.htm
https://support.kaspersky.com/KS4Exchange/9.6/en-US/28871.htm