How to Undo in Slack: What Cmd+Z Undoes and What It Cannot

To undo in Slack, press Cmd+Z on a Mac or Ctrl+Z on Windows. In the message box it undoes your typing. Right after you send a message, with the message box empty, the same keys open an Unsend message dialog that pulls the message back. Most other actions, such as deleting a message or removing a reaction, have no undo at all. On October 27, 2026 we tried 8 common actions in our Free test workspace in Slack's web app and recorded what Cmd+Z did after each one.

Slack's own shortcut list, opened with Cmd+/, shows the two undo shortcuts it supports:

What Cmd+Z undid in our test

Unsend a message you just sent

This is the closest Slack has to undo send. After we sent a test message, pressing Cmd+Z with an empty message box opened this:

We clicked Unsend. The message disappeared from the channel, and its text was back in the message box, ready to fix and send again.

It did not work every time. We repeated the test 14 more times in the same browser tab, pressing Cmd+Z between 1 and 90 seconds after sending, and the dialog did not open again. An earlier test of ours on September 30 had unsend work about 12 seconds after sending and fail at 20 seconds. Slack's help page gives the conditions: within 15 seconds of sending, without leaving the conversation, with an empty message box, and only on desktop. If the dialog does not open, delete the message from its More actions menu instead. Other people may already have seen it, and Can Slack see deleted messages covers who can still read it.

Deleting a message cannot be undone

Slack asks first, and says so in the dialog:

After we clicked Delete, the message was gone and Cmd+Z did nothing. If you need the text back, check whether someone quoted or forwarded it.

Leaving and archiving channels

/leave took us out of the test channel at once and moved us to another channel, with no toast and nothing for Cmd+Z to undo. To go back, find the channel in the channel browser and join it again; private channels need an invite.

/archive opened a confirmation dialog instead:

After we archived it, there was no undo toast either. We then unarchived the channel and it came back with its messages. Archiving a Slack channel shows where the Unarchive option lives.

Undo in a Slack canvas

In a channel canvas, Cmd+Z removed the last line we typed. A second press did not remove the first line, which Slack had turned into the canvas title, and Cmd+Shift+Z did not bring the removed line back. Treat canvas undo as a short-term fix. To keep a copy of a canvas before a big edit, export the canvas.

Formatting undo

When Slack turns *text* or a pasted markdown link into formatting as you type, one Cmd+Z right after it reverts the formatting. Slack markdown not working covers that case and the setting that turns auto-formatting off.

FAQ

Can an admin restore a deleted message?

Not from Slack's admin pages. On the Free plan Slack does not keep deleted messages. On paid plans an Owner can choose to save edits and deletions, and then a deleted message can turn up in a full export; Can Slack see deleted messages has the details.

Is there undo on the Slack mobile app?

Slack's help says unsend is desktop only. On a phone you can edit or delete a message instead.