What You Should Know About a Slack Messages Retention Policy

An effective retention policy should reflect the rules, limitations, and standard settings of the Slack platform.

What You Should Know About a Slack Messages Retention Policy

Slack has changed how workers at many organizations communicate. After all, before Slack, there was no efficient way for coworkers to send memes and recipes to each other without emailing them. 

Yes, we know, Slack has ALSO helped employees, especially remote employees, communicate with and learn from their colleagues more efficiently than was possible before. 

But thanks to all those messages, organizations must develop and implement a Slack messages retention policy to ensure that messages are not inadvertently deleted, edited, or lost. If an organization doesn’t do so, they may run into trouble during litigation, especially during discovery, as opposing parties may claim that failing to have a Slack messages retention policy constitutes spoliation of evidence. 

An effective retention policy should reflect the rules, limitations, and standard settings of the Slack platform. That means the people tasked with creating their organization’s Slack messages retention policy need to understand key aspects of the platform’s retention policies, including how to delete Slack conversations, Slack’s “close conversation” meaning, how to bulk delete Slack messages, Slack edit message time limits, and Slack edit history. 

When completed, an organization’s Slack messages retention policy should include procedures for recovering deleted Slack messages, managing the message history limit, and preserving old messages.

Recovering Deleted Slack Messages

Slack does not have a “deleted” folder or recycle bin function. As a result, when employees delete Slack messages or threads, those messages could be gone forever.

Organizations have several options for recovering Slack deleted messages or a deleted Slack workspace. The Slack API provides an automatic export mechanism so organizations can export their Slack content to pre-approved third-party platforms. However, this functionality requires organizations to purchase a Slack Enterprise Grid subscription and to contact Slack to enable the function in the API. 

Alternatively, organizations can use Slack’s built-in import/export tool to export their Slack content manually or at scheduled intervals (e.g., daily or weekly). However, only subscriptions at the Business tier and above may schedule automatic exports. Slack exports data through its built-in tool in JSON format, which can be downloaded to a local device or cloud storage platforms. Organizations can import these files back into Slack to recover messages that were deleted after that export was created. 

How to Deal with Slack’s Message History Limit

Slack imposes message and file limits on free workspaces. As a result, Slack auto-deletes messages from those workspaces. However, organizations with paid subscriptions do not have message or file limits. 

Slack ordinarily allows admins to view and search messages and files for the last 90 days. When a workspace reaches the message history/visibility limit, the platform hides messages and files older than 90 days. Workspace owners have two options in Slack’s data retention settings for managing hidden messages and files. They can choose to keep all messages and files or auto-delete any messages and files after 90 days. 

Organizations can avoid losing easy access to messages and files that hit Slack’s message history limit either by using the Slack API to set up integrations with third-party approved platforms to automatically export data (with the required subscription tier), or by scheduling regular exports or manually exporting data through the built-in import/export tool. 

Does Slack Delete Messages for Everyone?

Unlike with paid subscriptions, a free Slack subscription limits storage capacity. Once an organization using a free workspace hits its message and data limits, Slack may either delete the oldest messages or prevent users in the workspace from sending new messages. 

On Slack, any user can delete the messages they’ve written, although workspace owners can restrict this ability. Alternatively, users can unsend messages within 15 seconds, which returns a message from the channel to the message input screen. 

When a user or workspace owner deletes Slack messages, the messages get erased from every user’s instance. Deleting the original message in a thread also deletes all the responses in the thread. 

Users who create Slack channels can also archive/delete the channel history. Archiving the channel will delete it for all users on the workspace. 

Best Practices for Slack Messages Older Than 90 Days

Organizations can adopt procedures to ensure they don’t inadvertently lose old Slack messages because of employee actions or Slack’s own data retention policies. Organizations’ policies will necessarily vary based on the Slack tier they have. Best practices for organizations to follow for retaining Slack messages include:

  • For free workspaces, administrators should set reminders to export their company’s Slack data regularly, such as daily or weekly.
  • Administrators of paid workspaces can schedule Slack’s built-in import/export tool to export data regularly. However, administrators should monitor the export process, since large batches of data may require multiple exports. Plus, technical problems such as loss of internet connection can interrupt the process.
  • Workspace administrators should restrict users’ ability to delete their messages.

  • For Enterprise tier workspaces, administrators should set up integration between the Slack workspace and a third-party data storage or eDiscovery platform to ensure that Slack data is automatically backed up in another location outside Slack. 

Why Does Slack Delete Old Messages?

For those of us always bumping up against our iCloud/Dropbox/Google Drive storage limits, it may seem odd for a company the size of Slack to delete users’ old messages. But Slack knows its users and recognizes that most data in its workspaces falls into one of three categories: redundant, obsolete, or trivial. 

If Slack did not prune its users’ messages, it would incur unnecessary data storage costs as well as other liabilities such as the risk of data breaches and reduced performance of its product. Of course, Slack also restricts the ability for free workspaces to retain old messages because it can—those users don’t contribute to Slack’s bottom line.

Why Do Slack Direct Messages Disappear?

Users may find that old Slack messages disappear from their sidebar as they start new direct messages. Slack has said that its direct messages list limit keeps the channel list organized since, by default, the sidebar lists channels, apps, and direct messages together. 

However, users can make Slack show more direct messages. Users can change their sidebar settings to separate their direct messages and apps from the channels in the sidebar. They can also “star” messages to keep them displayed on the sidebar. Or, they can create a new “direct messages” section in the sidebar and move into that section direct messages they want to keep.


Slack might make it easy for employees to share memes and recipes, and for remote employees to feel like they’re part of the team. But its retention policies can make life miserable for their IT colleagues.

Given the problems that could arise in discovery—and litigation generally—when they do not retain their Slack messages, organizations need to understand the retention policies their Slack subscription provides them. 

With that information in hand, they can, if need be, design their own Slack messages retention policy that retains messages and files that would have otherwise been lost to the sands of time because of the Slack tier they’re on.

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