When custom sidebar sections (folders) created on your desktop Slack app do not appear, remain collapsed, or show different channel groupings on your mobile app, web client, or secondary computer, Slack’s client-side preference sync has stalled. Custom sidebar sections are a cloud-synchronized preference; when devices show inconsistent folder layouts, it is caused by local cache corruption, an outdated mobile client, or an active device running on a different account tier.
Fast Fix
Force a sync refresh on your desktop client by selecting Help > Troubleshooting > Clear Cache and Restart. On mobile, tap your profile picture, select Preferences > Advanced, and tap Reset Cache. If your workspace recently downgraded to a Free plan, custom sidebar sections are automatically disabled, as they require a paid subscription.
Diagnostic Snapshot
- Symptom: Sidebar folders (custom sections) exist on the desktop app but are missing, unsorted, or empty on mobile or the web client.
- Component: Slack Cloud User Preferences API (
users.prefs.set) vs. local client state. - Plan Dependency: Pro, Business+, or Enterprise Grid required. Free plans do not support custom sidebar folders.
- Scope: Single user profile across multiple devices.
Diagnostic Path: Pinpointing the Sync Break
Follow this workflow to determine why your sidebar sections are not matching across devices:
Sidebar Folders Missing on Secondary Device
│
Check Workspace Subscription Tier
│
Is the workspace on a paid plan?
/ \
YES NO
/ \
Check Web App Baseline [Free Plan Limit]
(<https://app.slack.com/client>) Custom sections are disabled
│ on Free tiers; channels revert
Do folders appear on Web? to default "Channels" list.
/ \
YES NO
/ \
[Target Device Bug] [Originating Desktop Bug]
Target device has a The desktop failed to write
stale local cache; changes to Slack's cloud;
reset mobile cache. force a preference write.
Step-by-Step Resolution
Step 1: Confirm Workspace Plan Eligibility
Custom sidebar sections (the ability to create folders, name them, and organize channels and DMs inside them) are exclusively available on paid Slack plans (Pro, Business+, Enterprise Grid):
- If your workspace downgraded to the Free plan, Slack immediately collapses all custom sections.
- All channels and direct messages are returned to the default system categories: “Channels” and “Direct messages.”
- If your organization is on a paid plan, continue to Step 2.
Step 2: Establish the Cloud Baseline in a Web Browser
Before troubleshooting device settings, verify what is actually saved on Slack’s cloud servers:
- Open Google Chrome, Microsoft Edge, or Safari.
- Sign in to your workspace at
https://app.slack.com/client. - Check the left sidebar:
- If folders appear correctly in the browser: Your desktop successfully saved your layout to the cloud. The issue is isolated to your secondary computer or mobile app failing to pull the update. Proceed to Step 3.
- If folders are missing in the browser: Your primary desktop application is stuck in an offline or local-only caching state. It never uploaded your custom sections to Slack’s servers. Proceed to Step 4.
Step 3: Clear Cache on the Desynchronized Target Device
If your mobile app or second computer refuses to display the folders visible on the web:
- On iPhone / iPad (iOS):
- Open Slack and tap the You tab (profile picture) in the bottom-right corner.
- Tap Preferences > Advanced.
- Tap Reset Cache and confirm. The app will close and rebuild its local database upon relaunch.
- On Android:
- Open Android Settings > Apps > Slack.
- Tap Storage & cache.
- Tap Clear Cache (do not tap “Clear Data” unless you are willing to re-authenticate).
- On a Secondary Desktop (Windows / macOS):
- Click Help > Troubleshooting > Clear Cache and Restart.
- If the client persistently fails to match the web view across restarts, see [Troubleshooting: Slack Browser vs Desktop App Sync Mismatch]](http://www.saasopsmanual.com/slack-troubleshooting/slack-login-connection/slack-browser-vs-desktop-sync-mismatch)
Step 4: Force a Cloud Preference Write on the Originating Desktop
If the web browser was also missing your custom folders, your primary desktop client needs to force-push its current layout:
- Open your primary desktop Slack app.
- Create a temporary new section: right-click any channel, select Move channel, and choose New section.
- Name it “Test” and click Create.
- Drag a channel into the “Test” folder, wait ten seconds, and drag it back to its original location.
- Delete the “Test” section.
- This manual update forces the desktop client to issue an immediate
users.prefs.setAPI call to Slack’s cloud, overwriting the stale server record with your current layout.
Step 5: Resolve Local Data Corruption
If your desktop application repeatedly drops sidebar sections, forgets folder order, or closes open direct messages after every restart, the local client’s configuration files may be corrupted.
- A damaged local configuration prevents preference writes from completing.
- To repair local database corruption, follow the recovery procedures in Troubleshooting: Slack “Local Data Corruption” repair guide and Fix: Slack “Direct Message” disappearing after Restart.
Account and Enterprise Grid Check
If you are part of a company using Slack Enterprise Grid with multiple workspaces:
- Custom sidebar sections are configured on a per-workspace basis, not organization-wide.
- Creating a custom folder in your
#engineeringworkspace does not automatically duplicate that folder in your#general-corpworkspace. - Ensure you are reviewing the sidebar of the exact same workspace on all devices.