Recover deleted mail items in the Exchange Online environment | Deleted mail flow | 3#7

Page 1 of 26 | Recover deleted mail items in the Exchange Online environment | Deleted

mail flow | 3#7

Written by Eyal Doron | o365info.com | Copyright © 2012-2015

Recover deleted mail items in the

Exchange Online environment | Deleted

mail flow | 3#7

In the current article, we will review the following subjects:

The flow of a “deleted mail item” in an Exchange base environment for a

standard mailbox and for Litigation Hold or In-Place Hold enabled mailbox.

The subject of Deleted Item retention policy, the Exchange server policy that

removes deleted mail items after a specific time period and the ability to extend

the default value.

The meaning of the terms Soft delete versus Hard delete.

http://o365info.com/recover-deleted-mail-items-in-the-exchange-online-environment-deleted-mail-flow-part-3-7


https://il.linkedin.com/in/eyaldoron1

http://o365info.com/


mail flow | 3#7


As Exchange Online administrator, we will need to understand the deleted mail flow

for two major reasons:

1. To be able to prepare in advance, for a business need in which we need to

provide the ability for recovering mail items for a longer period than the

“standard 14 days’ period”.

2. To be able to provide the right answer for our users, in a scenario in which our

user asks us to recover for then deleted mail items.

For example, in case that the user report that the mail item was deleted two

months ago and, we did not use the option of Litigation Hold or In-Place Hold, the

answer is that the mail item cannot be recovered!

The Recoverable Items folder and deleted mail item life

cycle

Before we start with the detailed description of the “deleted mail item life cycle” it’s

important that we understand the logic of the Recoverable Items folder.

As mention, In Exchange Online environment mail items that were deleted from the

Exchange inbox “Recycle bin” (the Deleted items folder) will be moved to

the Recoverable Items folder or, if we want to be more specific, to the Deletion

folder.

The main question is: for how long this “deleted mail items” will be kept in

the Deletion folder?

The answer depends on the specific setting of the Exchange Online mailbox.

Case 1– in case that the mailbox considers as “standard mailbox” the deleted mail

items will be considered as “recoverable” for a period of 14 days.

Case 2– in case that the mailbox considers as Exchange Online mailbox with

Litigation Hold or In-Place Hold enabled, the deleted mail items will be considered

as “recoverable” for a period that will be defined by the Litigation Hold or In-Place

Hold policy (a specific time period longer than 14 days or forever).






mail flow | 3#7


The Recoverable Items folder purpose and the relevance for the

subject of deleted mail items.

The Exchange single item recovery architecture and the Recoverable Items

folder can be considered as sophisticated architecture and an infrastructure that

was created for providing many types of services.

In the current article series, we will relate only to the “part” that relate to the subject

of storing and recovering deleted mail items via the Recoverable Items folder.

By default, the Recoverable Items folder can help us to deal with a scenario of

Soft deleted and Hard delete for a period of 14 days. This “limitation” is dictated by

the Deleted Item retention policy.






mail flow | 3#7


The Exchange architecture provides a tool that will enable us to “bypass” the

limitation that is imposed by the Deleted Item retention policy for a specific user

mailbox or for multiple mailboxes.

The name of the Exchange mechanism that enable us to “bypass” the limitation

described as Litigation Hold or In-Place Hold.

Recoverable Items folder, Litigation Hold and, In-Place

Hold

One of the most confusing and unclear subject in the Exchange server architecture

is the subject of Litigation Hold and In-Place Hold.






mail flow | 3#7


In the current article, we will not “dive” into a detailed description of these

components.

To simplify the understanding Exchange Litigation Hold and In-Place Hold, we can

relate to these components as a “tool” or mechanism that unable to use to override

the values of the Exchange Deleted Item retention policy that is applied on the

Exchange mailboxes.

For example –the default Exchange Online Deleted Item retention value is 14

days.

By using the option of Litigation Hold or In-Place Hold, we can set a

different Deleted Item retention policy to specific Exchange users.

For example, when we apply Litigation Hold and In-Place Hold to a specific mailbox,

we can decide what will be the value of the Deleted Item retention policy.

We can set the value of the Deleted Item retention policy to months, years or

even forever.






mail flow | 3#7


Litigation Hold versus In-Place Hold

The Litigation Hold mechanism is applied for all of the items in a specific mailbox

such as – calendar items, contact items mail items etc.

The option of In-Place Hold enables us to define more refined deleted mail item

policy.

For example, we can decide to apply the -Place Hold only to calendar items from a

specific date, etc.

In reality, the difference between Litigation Hold and In-Place Hold is much more

comprehensive but for our purpose, we can be satisfied with this simple

explanation.

Deleted mail item flow and “Life Cycle”

To be able to unveil the mystery of the Recoverable Items folder, let’s review the

object of Deleted mail item flow and “Life Cycle”.

We can classify the different “deleted mail items scenarios” in Exchange

environment to two major groups:

1. Standard mailbox – Exchange mailbox that is subject to the default Deleted

Item retention policy.

2. Exchange mailbox with a Litigation Hold or In-Place Hold enabled – an Exchange

mailbox that is not subject to the default Deleted Item retention policy.

Instead, have a “special” or dedicated Deleted Item retention policy.






mail flow | 3#7


What is the Exchange Deleted Item retention policy?

The term – “Deleted Item retention policy” define an Exchange process that can

be described as garbage collection of non-relevant objects (mail items).

Technically speaking, when a user decides to delete a specific mail item, the

meaning is that the mail item is not relevant or not needed for the user.

When a user deletes mail item, the mail item is not acutely deleted but instead,

moved or relocated to a new folder – the Deleted items folder.

Technically speaking, the user doesn’t need to “empty or clean the Deleted items

folder. In case that an Exchange user doesn’t bother to empty the Deleted items

folder, the “deleted mail item” will stay in the Deleted items folder forever.

The only disadvantage for not emptying the Deleted items folder is that the

deleted mail item considers as part of the user mailbox quota and over time, the

deleted mail items will consume a significant part from the user mailbox quota.






mail flow | 3#7


So let’s assume that for this reason and for a proper management of mailbox data,

the user decides to empty the content of the Deleted items folder.

The questions now are:

Q1: What happened to the mail items that were deleted from Deleted items

folder? Are they lost forever?

A1: When the user empties the Deleted items folder (delete mail items that were

saved in the Deleted items folder) the mail items are not deleted but instead,

moved or

“re located”, to an additional folder named: Deletion (one of the folders that are

include in the Recoverable Items folder).

Q2: Can the user access the content of the Deletion folder?

A2: The answer is “yes”. For example, Outlook user, can choose the option- recover

deleted items. This option will enable him to view the content of

the Deletion folder. The user will see a list of the mail items, that was deleted from

the Deleted items folder.






mail flow | 3#7


Q3: Is there any “time limitation” for the mail items that are saved to


A3: Yes there is. The Exchange component that dictates for how long the mail items

will be saved in the Deletion folder is the Deleted Item retention policy.

By default, the Deleted Item retention policy is configured so “keep” mail items in

the Deletion folder for a period of 14 days.

In Exchange on-Premises environment, the Exchange administrator can configure

the default value of the Deleted Item retention policy to any desired period.

In Exchange Online environment, the default value of the Deleted Item

retention can be extended over to a maximum period of 30 days.

The reason for this time limitation that are being enforced by the Deleted Item

retention is the process that I described as: “garbage collection”.

The Exchange server, need to manage the user mailbox data effectively.

The meaning – verify that the user mailbox will be restricted to a predefined

amount of storage and that this “storage” will be managed in an effective manner.

“new deleted mail items” will be saved and “old deleted mail items” will be removed

(deleted).

Q: What is the Exchange Deleted Item retention policy?

A: The Deleted item policy is an Exchange server policy, which “attached” to the

Recoverable Items Folder.

The purpose of the “Deleted item policy” is to optimize the management of

the Recoverable Items folder partition.

By default, the Recoverable Items folder partition serve as a temporary storage for

deleted mail items.

The Recoverable Items folder storage, provide a “grace period”, in which users can

“regret” and recover mail items although the mail was deleted from the inbox

“Recycle bin” (the Deleted items folder).






mail flow | 3#7


The Exchange Deleted Item retention policy serves as a “gatekeeper” or as the

“Exchange janitor”, that help the Exchange to manage his storage effectively by

keeping the Recoverable Items folder neat and tidy.






mail flow | 3#7


Q1: Does Exchange Online graphic management interface includes an option for

change the default value of the Deleted Item retention policy?

A1: No, the only way for extend the default value of the Deleted Item

retention policy to a time period of 30 days, is by using a PowerShell command.

The process or running the PowerShell command, will be needed to be

implemented for each new Exchange Online mailbox that will be created in the

future.

In the following screenshot, we can see the interface that is available when using

Exchange on-Premises 2010 version. The value of the Deleted Item retention is

set by the database level under the section of – Keep deleted items for(Days):






mail flow | 3#7


Q2: What will happen to a deleted mail item after 14 days?

A2: Exchange server will permanently delete all the mail items that save in

the Deletion folder that their “age” is over 14 days.

Q3: Is there any way for recovering mail items that were deleted from


A3: No, there is no way!

Q4: Is there any way for “extending” the Deleted Item retention policy for a longer

period of for unlimited time?






mail flow | 3#7


A4: Yes, Exchange Online and Exchange on-Premises server (Exchange version

2013) support two types of “solutions” that enable us to “override” the limitation

that is opposed by the

Deleted Item retention policy.

The available options are:

Exchange litigation Hold

In-Place Hold

When using one of this option, we are “removing” the time limitation that applied

on the deleted mail items that stored in the Deletion folder and the Purges folder.

Soft delete versus Hard delete.

Before we continue, I would like to briefly review two terms that relate to the flow

of the deleted mail item – Soft delete and Hard delete.






mail flow | 3#7


Soft Delete

When a user deletes a file and then, delete the file from the Deleted items folder,

the operation considered as Soft Delete.

We use the term “Soft” because – although the mail items were deleted from

the Deleted items folder, the file is not really deleted.

The user still of an option to recover the mail item by himself for a period of 14

days.

The “operation” of Soft Delete can be implemented by using the keyboard key

combination: SHIFT + DEL.

When select mail item and press on the combination keyboard key – SHIFT + DEL,

the deletion “bypass” the step in which the mail item sent to the Deleted items

folder and instead, the mail item sent directly to the Deletion folder.

Hard Delete

The term “Hard Delete” define a scenario in which the user access the content of

the Deletion folder (the folder that store mail items that were deleted from

the Deleted items folder) and, delete the mail item\s that store in this folder.

Theoretically, we can assume that is this scenario the mail item is “lost forever” but

in reality, although the user deletes the mail item\s from the Deletion folder the

mail item is not deleted but instead, relocated to the Purges folder.

We use the term “hard” because in this scenario, the user “lost” his ability to recover

the mail item by himself.

Only the Exchange administrator has access to the Purges folder and, only the

Exchange administrator can recover mail items that stored in this folder.

Note – an exception for this “rule” that enables “standard user” to access

the Purges folder is a utility named – MFCMAPI, which we will review in the next

section.






mail flow | 3#7


General thoughts about Soft delete and Hard delete.

User (mailbox owner) have the ability to implement an event of:

1. Standard mail item deletion

2. Soft delete

3. Hard delete

The Outlook\OWA mail client enables a user to recover mail items in a scenario of

1. Standard mail item deletion

2. Soft delete

The Outlook\OWA mail client doesn’t include an option that enables users to

recover mail items in a scenario of Hard delete, in which the mail item was moved

to the Purges folder (or to the DiscoveryHolds folder in case that we use the

option of In-Place Hold).






mail flow | 3#7


Deleted mail item flow scenarios

To understand better the purpose and that way that Recoverable Items

folder “work”, let’s review three scenarios of “deleted mail item flow” in an

Exchange based environment.

To demonstrate the “deleted mail item flow” we will review three different

scenarios:

Scenario 1: Standard Exchange mailbox

Scenario 2: Exchange mailbox with Litigation Hold enabled

Scenario 3: Exchange mailbox with In-Place Hold enabled

Scenario 1: standard user mailbox (no use of Litigation Hold or In -

Place Hold)

Step 1 – user decides to delete a specific mail item. The mail item is “moved” to


Step 2 – the user decides to empty the Deleted items folder and delete all the mail

items that existed.

The mail items are not deleted but instead – relocated to the Recoverable Items

folder “partition”, to the Deletion folder.

The mail item will be kept in the Deletion folder for a period of 14 days. At the end

of the period of 14 days, all the mail item that are “older” then 14 days will be will

be permanently deleted.

Step 3 – as mention, each user has an access to the content of

the Deletion folder when using the option of – “recover deleted items”. In case that

the user decides to “empty” the content of the Deletion folder, the mail item is

relocated and placed on the Purges folder.

The mail item will be kept in the Purges folder for a period of X days until the “age”

of the mail items is more than 14 days.

At the end of the period of 14 days, all the mail item that are “older” then 14 days

will be will be permanently deleted.






mail flow | 3#7


We use the term “X days” because, we don’t know what was the age of the mail that

is located in the Deletion folder.

For example – in a scenario in which the mail item age that is located in the

Deletion folder is four days when the user deletes the mail item, the mail item will

be relocated and saved to the Purges folder for a period to 10 days.

The reason for the “10 days” period is that by default the Deleted Item

retention define the range of “14 days” for the Deletion folder +

the Purges folder”

Scenario 2: Exchange mailbox with Litigation Hold enabled

The option of Exchange Litigation Hold enables us to set a different value for the

deleted mail items stored in the Recoverable Items folder that is different than

the value of the Deleted Item retention policy.

When using the option if Litigation Hold, we are able to “block” the Deleted Item

retention policy that is applied on the Purges folder.






mail flow | 3#7


As mention, by default mail items within the Purges folder will be saved up to a

maximum period of 14 days.

When using the option of Litigation Hold, Exchange administrator can decide about

the time period in which the deleted mail items will be saved to the Purges folder.

The “time period” could be defined a specific value for the number of days or can

be set for an unlimited time period (for forever).

Note – the ability to use the Litigation Hold depend on the specific license that is

assigned to the Office 365 user. Only when using Office 365 plan E3 license or

Exchange license plan 2, the option of Litigation Hold is available.

The deleted mail flow in a scenario of – “Exchange mailbox with Litigation Hold

enabled” is almost identical to the former scenario of – standard mailbox.

The main difference is that now; the Exchange administrator could recover deleted

mail items locate in the Purges folder for the time period that was defined in the

Litigation Hold policy.

For example – in case that the Litigation Hold policy for the mail box was defined

with a value of 3,000 days. The Exchange administrator will have the ability to

recover deleted mail items that their “age” is up to 3,000 days.






mail flow | 3#7


Scenario 3: Exchange mailbox with In-Place Hold enabled

The option of – In-Place Hold, is similar to the Exchange Online option of – Litigation

Hold.

We will not review in details the differences between these two methods but

instead, just mention that the Exchange method of In-Place Hold, consider as more

advanced mechanism, that has more options and capabilities versus the Exchange

Litigation Hold.

The main difference between a scenario in which In-Place Hold is enabled versus

Litigation Hold is that when we use the option of – In-Place Hold, a new folder

named:

DiscoveryHolds folder is added to the hierarchy of the Recoverable Items folder.

When the Exchange Online mailbox configure as – In-Place Hold is enabled, the

logic of the deleted mail items flow is implemented as follows:






mail flow | 3#7


Step 1 – user decides to delete a specific mail item. The mail item is “moved” to


Step 2 – the user decides to empty the Deleted items folder and delete all the mail

items that exist in this folder.

The mail items are not deleted but instead – relocated to the Recoverable Items

folder “partition”, to the Deletion folder.

The mail item will be kept in the Deletion folder for a period of 14 days. At the end

of the period of 14 days, all the mail item that are “older” then 14 days will be will

be moved to the DiscoveryHolds folder.

Step 3 – In case that the user “empty” the content of the Deletion folder, the mail

is relocated and placed “Immediately” in the DiscoveryHolds folder.

The Exchange administrator will have the ability to access the content of

the DiscoveryHolds folder and recover\restore mail items, based upon the time

period value that was set by the In-Place Hold and based on the In-Place Hold

“terms” that was defend.

For example – in case that the In-Place Hold policy that was applied to the user

mailbox define to “hold” only calendar mal items for unlimited time period, the

Exchange administrator will have the ability to recover deleted mail item that

consider as “calendar mal items” for unlimited time period but this “ability”, could

not be implemented for other type of mail items such as contact mail item, note

mail items and so on.






mail flow | 3#7


Recoverable Items Folder and Mailbox quota

Each time when a new Exchange mailbox is created, Exchange allocates a dedicated

storage quota for the Recoverable Items folder.

The quota that is allocated to the user mailbox is not affected in any way by the

quota that allocated to the Recoverable Items folder.

In Exchange Online environment, each mailbox has a storage limit of 50 GB and

additional

30 GB storage allocated for the Recoverable Items folder.






mail flow | 3#7


When we apply Litigation Hold or In-Place Hold for an Exchange Online mailbox,

Exchange Online, automatically extend the Recoverable Items folder quota size to

100 GB.

To demonstrate the subject of – Recoverable Items folder and mailbox quota, let’s

use the following example.

John is an Exchange Online user who has a “standard mailbox”.






mail flow | 3#7


To be able to see the default size of the Recoverable Items folder partition, we will

use the following PowerShell command:

Get-Mailbox John | fl Recoverable*

In the following screenshot, we can see that Exchange Online allocate a “dedicated”

quota for the Recoverable Items folder that described as RecoverableItemsquota

We can see that the default Recoverable Items folder quota is 30 GB

After we have assigned the option of Litigation Hold to John mailbox and, run again

the same PowerShell command, we can see that the Recoverable Items

folder quota is 100 GB

Stretching the Exchange Deleted item policy

In Exchange on-Premises environment, Exchange administrator can decide how to

set the default value of the Deleted Item retention.






mail flow | 3#7


In Exchange Online environment, the default value of the Deleted item policy is set

to 14 days.

For Office 365 customers who have purchased Office 365 business license, this

value cannot be updated into “higher” value.

For Office 365 customers who have purchased Office 365 Enterprise E1, E3, E4

licenses or Exchange plan 2 license, Exchange Online administrator have the

privilege to extend the default value up to 30 days.

The ability to “starch” the value of the Deleted Item retention policy is

implemented by using PowerShell command.

The property that represent the value of the Deleted Item retention policy is –

“RetainDeletedItemsFor”






mail flow | 3#7


In the following screenshot, we can see we can see an example to the default value

of the Deleted item policy.

The value of the property RetainDeletedItemsFor is 14 days.

To change this value of the Deleted Item retention policy, we can use a

PowerShell command.

For example, to “extend” the Deleted Item retention policy of John mailbox up to

30 days, we can use the following PowerShell command:

Get-Mailbox John| Set-Mailbox -SingleItemRecoveryEnabled $True -RetainDele

tedItemsFor 30

In the following screenshot, we can see that the value of

the RetainDeletedItemsFor was updated in now the value is: 30 days.






mail flow | 3#7


In case that we want to test this “Hard limit”, let’s use the PowerShell with a value

greater than 30 days.

In the following example, we try to use the PowerShell command with a value of 31

days.

The result is the following error:

The operation on mailbox “John” failed because it’s out of the current user’s write

scope. The value of properties ‘RetainDeletedItemsFor’ exceeds the maximum

allowed for user ‘John’ with license ‘BPOS_S_Enterprise’.

In case that we want to extend the value of the Deleted Item retention policy for

all of the Exchange Online users, we can use the following PowerShell command:

Get-Mailbox | Set-Mailbox -SingleItemRecoveryEnabled $True -RetainDeletedI

temsFor 30

Additional reading

Configure Deleted Item retention and Recoverable Items quotas

Change the deleted item retention period for a mailbox in Exchange Online

Single Item Recovery in Exchange Server 2010





https://technet.microsoft.com/en-us/library/ee364752(v=exchg.150).aspx

https://technet.microsoft.com/en-us/library/dn163584(v=exchg.150).aspx

http://blogs.technet.com/b/exchange/archive/2009/09/25/3408389.aspx

Documents

Recover deleted mail items in the Exchange Online environment | Deleted mail flow | 3#7