What is Poison Mailbox & How to Check Quarantine Mailbox in Exchange 2013/2010

In this article, you will get the information related to What is Poison Mailbox & How to check quarantine mailbox in Exchange server 2013/2010. Let’s proceed to the discussion in detail.

What is Poison Mailbox & Quarantine Mailbox?

There are just a basic concept behind the Poison mailbox, actually the unexpected activity (holding the sending queue, or getting into not responding situations, having more than 5 threads in queue and not processed till 60 seconds) found from a mailbox in an Exchange Server then the mailboxes which are holding these type of messages are called poisoned mailboxes, which generates crash reports continuously or sometimes. Exchange information store isolates these kinds of mailboxes and make an entry in their registry and also update the same in other Exchange server registry in case of a DAG. These type of mailboxes are also called Quarantine mailboxes or Flagged Mailboxes. Poison mailboxes cannot be accessed till that time it is in quarantine or isolation.

Poison Mailbox Registry

You can find the registry entry for poisoned mailbox at below mentioned the location.
For the total number of crashes:
For last crash time:

How to Check Quarantine Mailbox?

To check for the quarantine mailboxes run below-mentioned commands:
Get-Mailbox | Get-MailboxStatistics | Where {$_.IsQuarantined –eq $True}
After finding a mailbox quarantine or poisoned, you could go through below resolution section for fixing the mailbox poison issue.


Exchange Information Store keep watching the activity on poisoned mailbox, if there is not any crash report is detected till 6 hours from that user mailbox then the information store put the mailbox online and erase the registry from all Exchange servers in a DAG.
In that case, If you have resolved the cause of mailbox crash, and you are sure that the mailbox would work properly, then you can manually delete the registry entry and mount the mailbox into the Exchange database.
If the mailbox(es) are continuously generating the crash report, then you have to go with the manual solution for repairing the corrupted Exchange mailbox.

Manual Solution

New-MailboxRepairRequest command could be used for repairing the corrupted mailboxes from Exchange Server. This command has some unique features, which are below:

  1. This command works on the online database, there is no need to unmount the database for repairing.
  2. It also allows repairing whether a single mailbox from Exchange server database or the complete database without dismounting.

There are four types of mailbox corruption mentioned below, which could be fixed using the New-MailboxRepairRequest command.

  1. Errors detected in search folder (SearchFolder).
  2. Errors in displaying a number of available items in a mailbox (AggregateCounts).
  3. Errors in the content display from the folder (FolderView).
  4. Errors detected in Folder Structure (ProvisionedFolder).

During running the New-MailboxRepairRequest command, the mailbox which is being repaired currently cannot be accessed.
The syntax of New-MailboxRepairRequest command:
New-MailboxRepairRequest –Corrupted_object [ObjectName] - CorruptionType [CorruptionType_above_mentioned]
An example of New-MailboxRepairRequest Command for checking a single mailbox corruption without any repair:
Get-MailboxRepairRequest –Mailbox abc@mailtest.com
An example of New-MailboxRepairRequest Command for checking all mailboxes corruption without any repair:
New-MailboxRepairRequest –Database “Database Name” –CorruptionType AggregateCounts –DetectOnly
An example of New-MailboxRepairRequest Command for repairing the mailboxes:
New-MailboxRepairRequest –Mailbox abc@mailtest.com –CorruptionType SearchFolder, AggregateCounts, ProvisionedFolder, FolderView
Note: New-MailboxRepairRequest command would only in Exchange 2010 SP1 and all above versions of Exchange Server. In that case, if you are having Exchange 2007/2003 then you have to go with ESEUTIL /r for soft recovery and ESEUTIL /cc “path_of_edb_file” for hard recovery of Exchange Database. With the help of ESEUTIL command, the complete Exchange Database would be unmounted first.

Exception Case

If you find that mailbox is repeatedly sending the crash report again and again, and the above-mentioned solution is not working, then you must have to repair those corrupted mailboxes with the help of any third party Exchange mailbox repair tool.

That’s all what I am to write about “What is Poison Mailbox & How to Check Quarantine Mailbox in Exchange 2013/2010”.


At last, we could observe from above sections that firstly we discussed what is poison mailboxes and quarantine mailboxes in Exchange database, then we saw the registry entry path of poison mailbox, then we discussed what is quarantine mailbox and then we discussed its manual solution. The solution was related to all version of Exchange but we discussed a specific command New-MailboxRepairRequest, which could be executed only in Exchange 2010, 2013 & 2016. At last, we also discussed that if every solution fails then, in that case, it is must use a third party tool for repairing the corrupted Exchange mailboxes.