Is Quota Exceeded warning displays, but quota has not been reached (4301206)

This is because the warning is triggered when items for the import mailbox or recoverable items folder reaches a certain percentage of the warning limit. For example, the default warning threshold is 95%. So, the Is Quota Exceeded warning displays when the import mailbox (or recoverable items folder) reaches 95% of the warning limit.

The warning displays when the warning limit threshold is reached, rather than when the actual size is reached, so the active mailbox doesn’t break with our direct action. It also creates a level of flexibility for the customer, so they can remediate the issue without breaking the active mailbox.

Configuring the threshold

The warning threshold can be configured in SysConfig > JEExplosion with values from 1 to 100% of mailbox size (or actually of -IssueWarningQuota or -RecoverableItemsWarningQuota parameters). The default value is 95%.

Example

Here’s an example:

• Mailbox limit is 50 GB
• Warning limit is 40 GB
• Prohibit send is 45 GB
• Prohibit send and receive is 50 GB

So, if you configure the warning limit to 90%, the Is Quota Exceeded warning is triggered when the mailbox reaches 90% of 40 GB.

Additional information

For reference, here are Microsoft articles about viewing and managing quotas.

• Regular quotas: https://docs.microsoft.com/en-us/Exchange/recipients/user-mailboxes/storage-quotas?view=exchserver-2019
• Recoverable items quotas: https://docs.microsoft.com/en-us/exchange/policy-and-compliance/recoverable-items-folder/clean-up-deleted-items?view=exchserver-2019