Set retention rules for mail and classic Hangouts

Use retention rules to control how long mail and classic Hangouts data is retained for eDiscovery purposes.

Before you set retention rules, we strongly recommend you read about how retention works.

WARNING: An improperly configured retention rule can cause the immediate and irreversible purging of data from user accounts. Use caution when creating or changing retention rules. We recommend that you test new rules on a small group of users before applying them to your entire organization.

Important information about messages and retention

Email threads are treated differently from individual messages

For email threads:

  • If one message in a thread is retained by a custom rule, the entire thread is also retained.
  • If a message in a thread isn't covered by any retention rules, only that message is expunged. The other messages in the thread are retained as required by applicable retention rules.
  • Retention rules based on labels use the date of the last-labeled message in a thread for retention purposes. See how this works in Example 1.
  • Vault treats undeleted draft messages just like every other message. If you create a default or custom retention rule, undeleted draft messages in your domain are also retained by the rule. You can choose Exclude drafts when creating creating a retention rule, and that rule does not affect draft messages. If a draft is deleted without being sent, it is expunged 30 days later, regardless of retention policies or holds.
Removal and expunging scenarios

Let's say that the Vault administrator creates a retention rule that has a retention period of 180 days. This rule applies to a message in users' mailboxes. The timeline for removal and expunging depends on what users do with this message.

Scenario 1: Users leave the message in their mailboxes

Let's say that the message is received on May 1.

What happens to this message:

  • The message is removed from user mailboxes on day 181, the day after the retention period expires. If the rule applies to a message in the trash, it is also removed at day 181.
  • The period before expunge begins. The Vault admin can still search for and find this message for 30 more days.
  • The message is expunged on day 211 (181 + 30 more days), which is November 28.

Scenario 2: On the day the message was received, users delete the message forever

The message is received and deleted forever on May 1.

What happens to this message:

  • The period before expunge goes into effect the day users deleted the message forever from their mailboxes.
  • Expunging is based on retention period: May 1 (send/receive date) + 180-day retention period. Expunge is on October 28.

Scenario 3: Further into the retention coverage period, users delete the message forever

The message is received on May 1. On day 40, users delete the message forever.

What happens to this message:

  • The period before expunging goes into effect on day 40.
  • Expunging is based on retention period: May 1 (send/receive date) + 180-day retention. Expunge is on October 28.
Note: If users delete the message forever within 30 days of the retention period expiration, the period before expunge can extend beyond the retention period.

Scenario 4: Further into the retention coverage period, users move the message to trash

The message is received on May 1. On day 160, users move this message to the trash. They do not empty the trash. In other words, they do not delete forever.

What happens to this message:

  • On day 181, the message is removed from users' trash. (After 30 days, Gmail's normal behavior is to expunge messages from the trash. But this message is removed at day 181 to adhere with the retention rule.)
  • The period before expunge begins.
  • The message is expunged on day 211 (181 + 30 more days). Expunge is November 28.

Additional retention examples

The following examples illustrate some of the different factors that affect how long messages are retained and when they are removed:

Example 1: Unlabeled messages do not extend the life of a thread

When you apply a label in Gmail, the label is applied only to messages already in that conversation. Future messages in that conversation are not automatically labeled. If a label-based custom retention rule applies to a message in a conversation, the rule retains all messages in that conversation until the date that the last labeled message is to be removed from the user’s mailbox. Replies to the last labeled message do not extend the retention period for that conversation.

Mail in this example is retained as follows:

  • Custom rule retains labeled messages for 3 years.
  • There is no default retention rule.

Action Description
1 A user applies a label on March 31, 2013.
2 All labeled messages are removed on March 31, 2016. The unlabeled reply is unaffected by the retention rule.

Example 2: Threads are retained by the custom rule with the longest retention coverage period

If a new reply to a labeled conversation is subject to another custom retention rule, the entire conversation is retained according to the longest retention period. Mail in this example is retained as follows:

  • Custom rule retains labeled messages for 3 years.
  • Custom rule retains messages sent_after: 2013-07-01 for 7 years.
  • There is no default retention rule.
Action Description
1 A user applies a label on March 31, 2013.
2 The last message is received on July 31, 2013.
3 Because the last message was received after July 1, 2013, the thread is removed 7 years after the last message was received.

Example 3: Messages protected only by a default rule do not extend the life of a thread

If a new reply to a labeled conversation is retained only by a default rule and matches no custom rule, it does not extend the life of the conversation. The portion of the thread protected by the custom rule is removed, while the messages protected by the default rule persist.

Mail in this example is retained as follows:

  • Default rule retains messages for 5 years.
  • Custom rule retains labeled messages for 3 years.
Action Description
1 A user applies a label on March 31, 2013.
2 The labeled messages are removed 3 years later.
3 The unlabeled message is retained by the default rule for 5 years.

Create a custom retention rule for mail and classic Hangouts

Custom rules can be based on organizational units, date ranges, or specific search terms. Custom rules always override the default rule, and if multiple retention rules apply to a message or file, it is retained according to the rule with the longest retention coverage period.

To create custom retention rules:

  1. Sign in to Vault.
  2. In the left navigation, click Retention.
  3. Click Create Rule.
  4. Choose where to apply the rule: Mail.
  5. Choose an organizational unit from the drop-down list.
  6. Choose what conditions must be met for messages to be covered by this rule:
    • Enter the sent date for messages subject to this rule. If you specify only a start date, the rule applies to all messages received after that date. If you specify only an end date, the rule applies to all messages received before that date.
    • Enter any terms that might appear in messages subject to this rule. You can also use search operators in this field.
      Note: Do not use wildcards (*) with retention rules.
    • Retention rules apply to draft messages by default. Check the box if you want this rule to exclude drafts.
  7. Choose how long to keep messages:
    • Choose indefinitely to permanently retain data that matches the parameters of this rule. Click Save to create the retention rule. You're done!
    • To discard messages after a period of time, enter the number of days, from 1 to 36,500.
  8. Choose what to do with messages past the duration you selected:
    • Choose the first option to expunge just the messages that users have already deleted.
    • Choose the second option to expunge all messages. This includes messages that are in users’ inboxes. It also includes messages that have already been deleted.
  9. Click Preview to display a list of messages or files that will be covered by this retention rule. Examine the list to verify that you've set the rule correctly. Make sure it does not permanently delete data that users may need.
    Warning: Vault immediately begins the process of purging data that exceeds the retention coverage period as soon as you submit a new rule. This can include data users expect to keep. Do not proceed to the next step until you’re sure the rule is configured correctly. 
  10. Depending on the type of rule you’re creating, you need to:
    • Click Save to create a retention rule that keeps messages and files indefinitely.
    • Click Continue to create a retention rule that expunges messages and files. Vault asks you to confirm you understand the effects of this retention rule. Check the boxes and click Save to create the rule.

Important notes

  • Email aliases in the Terms field—An email alias is an alternative email address that points to a primary email address. Custom retention rules don't automatically include email aliases. If you want to include email aliases, you must add them to the Terms field.
  • Renamed users—Custom retention rules aren't automatically modified when users are renamed. The retention rule continues to apply only to addresses that are explicitly in the Terms field of the rule. For example, if a rule applies to messages that include before@example.com and that user is renamed after@example.com, the retention rule applies only to messages sent to before@example.com.
  • Modifying a custom retention rule—You can modify a custom rule, but you must understand how that modification might impact retained data. Data is retained according to the most recent modification to the retention rule.

Set a default retention rule for mail and classic Hangouts

The default retention rule applies to all messages and files that are not covered by a custom rule or a hold. This includes files on My Drive and in Team Drives.

To set the default retention rule for your organization:

  1. Sign in to Vault.
  2. In the left navigation, click Retention.
  3. Under Default retention rules, click Mail.
  4. Check the Set a default retention rule box.
  5. Choose how long to keep messages:
    • Choose Indefinitely to permanently retain data. Click Save to create the default retention rule. You're done!
    • To discard messages after a period of time, enter the number of days, from 1 to 36,500.
  6. Choose what to do with messages after the retention period expires:
    • Choose the first option to expunge just the messages that users have already deleted.
    • Choose the second option to expunge all messages. This includes messages that are in users’ inboxes. It also includes messages that have already been deleted.
    Warning: Vault immediately begins the process of purging data that exceeds the default retention coverage period as soon as you submit this rule. This can include data users expect to keep. Do not proceed to the next step until you’re sure the rule is configured correctly. 
  7. Click Continue to create a retention rule that expunges data. Vault asks you to confirm you understand the effects of this retention rule. Check the boxes and click Confirm to create the rule.
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