Your Slack conversations are disappearing
Three months ago, someone in your friend group’s Slack shared a restaurant recommendation. You meant to save it. You remember the enthusiasm, the replies piling up, the person who typed “we HAVE to go.” You do not remember the restaurant’s name. You do not remember who posted it. And when you scroll back to find the message, it is gone.
Not archived. Not collapsed behind a “show more” button. Gone.
The 90-day wall
Slack’s free plan caps message history at 90 days. Anything older becomes invisible: you cannot view it, search for it, or even confirm it existed. After one year, Slack permanently deletes those messages and files entirely. No recovery. No export. No “we kept a backup just in case.”
Most people know this in the abstract. Few people feel it until a specific thread they need turns out to be on the wrong side of that 90-day line.
Paid plans remove the limit (the Pro plan starts at $8.75/user/month), but the workspaces where your personal life unfolds, friend groups, hobby communities, small open-source teams, almost never upgrade. The exchanges that matter most to you as a person, not as an employee, are usually the ones running on a free tier with a ticking clock.
What the deletion actually destroys
The loss is not primarily informational. You can Google the restaurant. You can ask your friend to name it again. The facts are recoverable one way or another.
What is not recoverable is the exchange itself. How someone phrased the recommendation. The digression about a similar spot in Osaka that two people had both visited without knowing. The cascade of heart-eyes emoji when the group collectively decided it was happening. That thread was a small piece of your social life, and it exists nowhere now.
Group chat on Slack occupies a register that no other medium captures. Email is formal. Texting is one-on-one and fragmented. Social media is a performance for an audience. A private group thread belongs to none of those categories: it is fast, unfiltered, collaborative. People type the way they would talk across a table. Humor compounds on the previous reply. Plans and nonsense coexist in the same scroll.
When that history resets, what disappears is the texture of the relationship. The people remain. The channel continues. But the accumulation of shared references, the running record of what you recommended, debated, and laughed about together, flattens back to zero every 90 days. The group retains its present tense but loses its past.
You never pin the ones that matter
Slack offers bookmarks and pins. In theory, you could flag every meaningful message as it happens. In practice, significance is invisible in the moment.
The restaurant tip felt trivial when it appeared. The late-night thread about whether anyone else is feeling burned out felt like venting, not a moment worth archiving. The logistics thread for a trip that became one of the best weekends of the year read like scheduling, not memory-making.
Meaning arrives late. The weight of an exchange often only becomes clear weeks or months afterward, when you want to look back and trace how something started. By then, the 90-day window may have already closed.
This is the same asymmetry that defeats manual journaling: you are asked to judge importance before importance reveals itself. The casual, spontaneous, unremarkable threads, the ones that later turn out to carry the most meaning, are the first to fall off the edge.
Community memory on borrowed time
The problem extends beyond personal groups. Developer communities, open-source projects, book clubs, and gaming guilds rely on free Slack workspaces because nobody wants to bill a volunteer community $8.75 per member per month. And every one of these spaces is losing its history on the same 90-day schedule.
For a small open-source project, channel history serves as institutional memory. The architectural debate that settled a key design question. The thread where a contributor walked a newcomer through the build system. The rough consensus about backward compatibility. When those threads disappear, the project loses the reasoning behind its own decisions. What remains is the code, stripped of the “why.”
For a personal hobby workspace, the loss shows up differently. The shared reading list that took months to build, gone. The seed of a project idea that started as a three-word message and grew into a plan, gone. The evening when someone was honest about struggling and four people stayed in the thread until midnight, gone. These were the threads that gave the group its identity. The space still exists. The identity does not.
The export escape hatch that nobody uses
Slack does offer a workspace export feature. On the free plan, you can export public channel messages. The output is a JSON dump: machine-readable, not human-readable. Nobody opens a folder of JSON files to reminisce about a thread from last quarter.
Private channels and DMs are excluded from the free export entirely. And the tool only captures what still exists at the time you run it. If you did not export before the 90-day cutoff, those messages are already beyond reach.
Even a timely export yields raw data: timestamps, user IDs, message bodies, channel names. Turning that into something you would actually want to read requires scripting, formatting, and motivation that almost nobody has. The feature was designed for IT administrators and legal compliance, not for someone trying to preserve a memory.
A silent, continuous erasure
What makes this deletion policy unusual is that it never stops. Your email inbox keeps everything until you actively delete it. Your photo library keeps everything until storage fills up. But Slack’s free tier runs a quiet, perpetual trim. Every day, the oldest day of visible messages falls off the far end.
No notification arrives. There is no “these messages will be removed in 7 days” warning. The scroll simply gets shorter. If you are busy for a week and do not look back far enough, you will not even realize something has been dropped.
This creates a particular psychological trick. The workspace feels alive and current, because you always see the most recent 90 days. But the apparent depth is an illusion. The channel looks like it has existed in its current form since the beginning, when in reality everything before a rolling cutoff date has been silently stripped away. What you have is not a permanent space with history. It is a conveyor belt with a fixed length.
Outrunning the clock
There are manual ways to beat the 90-day cutoff. Screenshots. Copy-pasting into a Google Doc. Running the export tool on a schedule. All of them require you to remember, to decide what is worth keeping, and to follow through repeatedly for months and years. The sustained success rate is close to zero, because the habit demands exactly the kind of ongoing vigilance that people abandon within weeks.
The alternative is to capture everything by default and let the sorting happen later. deariary does this: it reads your selected Slack channels daily and folds the day’s activity into a diary entry. Every thread and reply enters your diary well before the 90-day countdown reaches zero. You pick which channels to include; deariary handles the rest. (For setup details and data specifics, see the Slack integration guide.)
The output is not a message archive or a transcript. It is a diary entry where the restaurant recommendation sits next to your dentist appointment that morning and the gaming session that evening. The thread gains a dimension it never had inside Slack, because a day is more than one channel.
Three months from now, you will not try to scroll back through a workspace that has already forgotten. You will open a Tuesday’s diary entry and find the recommendation there, nested in the full shape of the day you were living when someone typed “we HAVE to go.”
What is already gone
If you have been on a free Slack workspace for more than 90 days, part of your history is already invisible. If it has been more than a year, part of it is permanently deleted.
There is nothing to do about what has already been erased. But the threads happening this week are still within the window. They will not be in three months.
The question is not whether those exchanges mattered. It is whether you will wish you could read them later, when the specific words and the specific warmth and the specific people in a specific moment are something you want back.
