Slack has become one of the most widely used communication tools for remote teams, freelancers, and businesses of all sizes. When it works, it works seamlessly. When it does not, the impact on productivity is immediate — missed messages, broken calls, failed file uploads, and notification blackouts that leave you out of the loop on important conversations.
This guide covers the most common Slack problems reported by users across desktop, mobile, and browser versions — with clear, step by step solutions for each one.
Slack Not Loading or Stuck on Loading Screen
One of the most frequently reported Slack issues is the app getting stuck on the loading screen, spinning indefinitely without connecting to the workspace.
Why It Happens
- Corrupted local cache files
- Outdated app version
- Network connectivity issues
- Slack server outage
- Conflicting browser extensions (for browser-based Slack)
Step by Step Fix — Desktop App
Step 1 — Check Slack’s Server Status Before doing anything else, visit status.slack.com to confirm whether the issue is on Slack’s end. If there is an active incident reported, the fix is simply to wait.
Step 2 — Check Your Internet Connection Open a browser and load any website to confirm your internet is working. If the connection is unstable, restart your router before proceeding.
Step 3 — Force Quit and Restart Slack
- On Windows: Press Ctrl + Shift + Esc to open Task Manager, find Slack, right-click and select End Task. Reopen Slack.
- On Mac: Press Cmd + Option + Esc, select Slack, click Force Quit. Reopen Slack.
Step 4 — Clear Slack Cache
- On Windows: Press Win + R, type %appdata%\Slack\Cache and press Enter. Select all files inside and delete them. Restart Slack.
- On Mac: Open Finder, press Cmd + Shift + G, type ~/Library/Application Support/Slack/Cache, delete the contents, and restart Slack.
Step 5 — Update Slack Go to Help in the menu bar and click Check for Updates. Install any available update and restart.
Step 6 — Reinstall Slack If none of the above work, uninstall Slack completely, download the latest version from slack.com, and reinstall.
Step by Step Fix — Browser Version
Step 1 — Clear Browser Cache and Cookies
- On Chrome: Press Ctrl + Shift + Delete, select Cached images and files and Cookies, set the time range to All time, and click Clear data. Reload Slack.
Step 2 — Disable Browser Extensions Open an incognito or private browsing window and try loading Slack. If it loads correctly, a browser extension is the cause. Disable extensions one by one to identify the conflict.
Step 3 — Try a Different Browser If Slack loads in a different browser, the issue is specific to your primary browser’s configuration.
Slack Notifications Not Working
Missing notifications is one of the most disruptive Slack problems — particularly for remote workers and freelancers who depend on Slack for client communication.
Why It Happens
- Notification permissions turned off at the operating system level
- Do Not Disturb mode active inside Slack
- Incorrect notification settings within a specific channel or workspace
- App running in background without proper OS permission
- Mobile battery optimisation blocking notifications
Step by Step Fix — Desktop
Step 1 — Check Slack’s Do Not Disturb Setting
- Click your profile picture or workspace name at the top left
- Look for the Do Not Disturb or Pause Notifications option
- If it is active, turn it off
Step 2 — Check Notification Preferences Inside Slack
- Go to Preferences (Ctrl + comma on Windows, Cmd + comma on Mac)
- Click Notifications
- Under Notify me about, make sure Direct messages, mentions and keywords is selected
- Confirm notification sounds are enabled
Step 3 — Check Operating System Notification Permissions
On Windows:
- Go to Settings, then System, then Notifications and actions
- Find Slack in the app list and make sure notifications are turned On
- Enable Show notification banners and Play a sound
On Mac:
- Go to System Settings, then Notifications
- Find Slack and confirm Allow Notifications is enabled
- Set alert style to Alerts rather than Banners for persistent notifications
Step 4 — Check Channel-Specific Notification Settings
- Open the channel where notifications are missing
- Click the channel name at the top to open channel details
- Click Notifications and confirm they are not muted or set to Nothing
Step 5 — Restart Slack Fully quit Slack and reopen it. Notification delivery sometimes resumes after a fresh session.
Step by Step Fix — Mobile (Android and iOS)
Step 1 — Check App Notification Permissions
On Android:
- Go to Settings, then Apps, then Slack
- Tap Notifications and make sure all notification categories are enabled
On iOS:
- Go to Settings, then Slack
- Tap Notifications and confirm Allow Notifications is turned on
- Enable Sounds and Badges
Step 2 — Disable Battery Optimisation for Slack (Android)
- Go to Settings, then Apps, then Slack
- Tap Battery and select Unrestricted or Don’t optimise
- Battery optimisation is one of the most common causes of delayed or missing Slack notifications on Android
Step 3 — Check Background App Refresh (iOS)
- Go to Settings, then General, then Background App Refresh
- Make sure Slack is enabled — this allows Slack to receive notifications when not actively open
Step 4 — Log Out and Log Back In
- Go to Slack settings on mobile
- Scroll down and tap Sign Out
- Sign back in and test notifications
Slack Calls Not Working — Audio and Video Issues
Slack’s built-in calling feature is useful but prone to audio and video problems, especially on lower-end hardware or unstable connections.
Why It Happens
- Microphone or camera permissions not granted to Slack
- Wrong audio input or output device selected
- Outdated audio or video drivers
- Firewall or VPN blocking Slack call connections
- Insufficient bandwidth for video calls
Step by Step Fix
Step 1 — Check Microphone and Camera Permissions
On Windows:
- Go to Settings, then Privacy and security, then Microphone
- Make sure Slack has permission to access the microphone
- Repeat for Camera under Privacy and security settings
On Mac:
- Go to System Settings, then Privacy and Security, then Microphone
- Confirm Slack is listed and enabled
- Repeat for Camera
Step 2 — Check Audio Device Selection Inside Slack
- Go to Preferences (Ctrl + comma or Cmd + comma)
- Click Audio and Video
- Under Microphone, confirm the correct input device is selected
- Under Speaker, confirm the correct output device is selected
- Click Test Microphone and Test Speaker to verify both work
Step 3 — Test Your Microphone Outside of Slack Open another application that uses the microphone — a voice recorder or video call app — and confirm the microphone works. If it does not work there either, the issue is a hardware or driver problem, not Slack.
Step 4 — Update Audio Drivers (Windows)
- Right-click the Start button and select Device Manager
- Expand Sound, video and game controllers
- Right-click your audio device and select Update driver
- Restart the computer after the update
Step 5 — Disable VPN Temporarily VPNs can interfere with Slack call connections. Disable your VPN, start a test call, and check whether audio and video work. If they do, configure your VPN to exclude Slack traffic or use a different VPN server.
Step 6 — Check Bandwidth Slack video calls require a stable connection of at least 1 Mbps upload and download. Run a speed test at fast.com. If your connection is below this threshold, switch to audio-only for calls or move to a better network.
Slack File Upload Failing
File upload failures in Slack are a common frustration, especially when sharing large files or working on a slow connection.
Why It Happens
- File size exceeds Slack’s upload limit
- Unstable internet connection during upload
- Slack workspace storage limit reached
- File type restricted by workspace admin
- Corrupted file
Step by Step Fix
Step 1 — Check File Size Slack’s maximum file size for a single upload is 1GB. Files larger than this cannot be uploaded directly. For large files, use Google Drive, Dropbox, or any cloud storage service and share the link instead.
Step 2 — Check Workspace Storage Free Slack workspaces have limited storage. If the workspace has hit its storage limit, uploads will fail. A workspace admin needs to delete old files or upgrade the plan.
Step 3 — Check Your Internet Connection File uploads require a stable connection. If your connection is dropping intermittently, the upload will fail partway through. Run a speed test and switch to a more stable network if needed.
Step 4 — Try a Different File Format If a specific file type consistently fails to upload, try converting it to a different format — for example, converting a large PSD file to a compressed PNG or a DOCX to a PDF — and uploading again.
Step 5 — Try Uploading via Browser If the desktop app is failing, open Slack in a browser and try uploading from there. Browser-based Slack sometimes handles uploads more reliably than the desktop client in certain network environments.
Step 6 — Share via Cloud Link If direct upload continues to fail regardless of file size, paste a shareable link from Google Drive or Dropbox instead. This is often the most reliable solution for large or complex files.
Slack Messages Not Sending
Messages stuck in a sending state or failing to deliver is a problem that can occur across both desktop and mobile versions.
Why It Happens
- Temporary network interruption
- Slack server issue
- App session timeout
- Corrupted app data
Step by Step Fix
Step 1 — Check Internet Connection A message that will not send is almost always a connectivity issue first. Confirm your internet is working by loading a website. If the connection dropped momentarily, Slack should resend queued messages automatically once it reconnects.
Step 2 — Check Slack Server Status Visit status.slack.com and check for any active incidents affecting messaging services.
Step 3 — Refresh the App
- On desktop: Press Ctrl + Shift + R on Windows or Cmd + Shift + R on Mac to force a full reload of Slack
- On mobile: Close the app completely and reopen it
Step 4 — Copy and Resend If a message is visibly stuck with a sending indicator, copy the message text, close and reopen Slack, and paste and resend it in the channel.
Step 5 — Clear Cache and Restart Follow the cache clearing steps from the first section of this guide, then restart Slack and attempt to send again.
Slack Running Slow or Using Too Much Memory
Slack is known for being a memory-heavy application. On older computers or systems with limited RAM, Slack can slow down significantly over time.
Why It Happens
- Too many workspaces loaded simultaneously
- Large message and file cache accumulated over time
- Slack hardware acceleration conflicting with GPU
- Too many sidebar items — channels, DMs, and apps — loaded at once
- Running other memory-intensive applications simultaneously
Step by Step Fix
Step 1 — Clear Slack Cache Follow the cache clearing steps from the first section. A large accumulated cache is the most common cause of Slack slowing down over time.
Step 2 — Disable Hardware Acceleration
- Go to Preferences (Ctrl + comma or Cmd + comma)
- Click Advanced
- Under Troubleshooting, find Hardware acceleration and uncheck it
- Restart Slack
Hardware acceleration works well on capable systems but causes performance issues on older hardware or certain GPU configurations.
Step 3 — Reduce Active Workspaces If you are signed into multiple Slack workspaces, each one runs in a separate session consuming memory. Sign out of workspaces you do not actively use and only keep the essential ones running.
Step 4 — Reduce Sidebar Clutter
- Go to Preferences, then Sidebar
- Hide sections you do not use — Apps, Drafts, unrelevant channel categories
- Fewer items loaded in the sidebar reduces the memory footprint
Step 5 — Use Slack in Browser Instead For users on low-RAM computers, using Slack in a browser tab consumes significantly less memory than the desktop application. Chrome or Firefox with Slack loaded as a tab is a practical alternative for resource-constrained systems.
Step 6 — Upgrade RAM if Possible Slack genuinely performs better with more RAM available. On a system with 4GB RAM running multiple applications, Slack will consistently feel sluggish. 8GB is the practical minimum for smooth Slack performance alongside other work applications.
Slack Search Not Working Properly
Slack’s search function is one of its most used features — and one of the most frustrating when it fails to return expected results.
Why It Happens
- Search index not fully loaded
- Incorrect search syntax
- Results filtered to wrong date range or channel
- App needs refresh
- Free plan message search limit reached
Step by Step Fix
Step 1 — Check Search Filters When search returns unexpected results, check the active filters. Click the filter icon next to the search bar and confirm:
- The date range is set correctly — not limited to a recent period
- The search is not restricted to a specific channel when you want to search all channels
- The person filter is not active unless you intend to filter by sender
Step 2 — Use Correct Search Syntax Slack supports specific search operators that improve accuracy:
- in:#channel-name — search within a specific channel
- from:@username — search messages from a specific person
- before:YYYY-MM-DD and after:YYYY-MM-DD — search within a date range
- has:link or has:file — search for messages containing links or files
Step 3 — Reload Slack Press Ctrl + Shift + R on Windows or Cmd + Shift + R on Mac to reload the app. Search indexes sometimes need a fresh session to return accurate results.
Step 4 — Check Plan Limits Slack’s free plan limits message search history. On a free workspace, only the most recent 90 days of messages are searchable. If you are looking for older messages, the workspace needs to be upgraded to a paid plan.
Slack Keeps Crashing or Freezing
Frequent crashes or freezing in Slack are typically caused by software conflicts, corrupted installation files, or hardware limitations.
Step by Step Fix
Step 1 — Update Slack Go to Help, then Check for Updates. Always run the latest version — crash fixes are frequently included in updates.
Step 2 — Clear Cache Follow the cache clearing steps from the first section. Corrupted cache files are a frequent cause of crashes.
Step 3 — Disable Hardware Acceleration Go to Preferences, then Advanced, then uncheck Hardware acceleration. Restart Slack. This resolves crashes on a wide range of hardware configurations.
Step 4 — Check for Conflicting Software Antivirus programs and security software occasionally conflict with Slack. Temporarily disable your antivirus and test whether Slack remains stable. If it does, add Slack to your antivirus’s exclusion list rather than leaving security disabled.
Step 5 — Reinstall Slack
- Fully uninstall Slack — on Windows use Apps and Features, on Mac drag Slack to Trash and empty it
- Download the latest installer from slack.com
- Install fresh and sign in
Step 6 — Check System Resources Open Task Manager on Windows or Activity Monitor on Mac while Slack is running. If CPU usage is consistently at 90 to 100% or RAM is fully consumed, the system hardware is the bottleneck rather than Slack itself. Closing other applications or upgrading hardware is the long-term fix.
Slack Two-Factor Authentication Problems
Two-factor authentication adds security to Slack accounts but occasionally creates login problems when authentication codes fail or are not received.
Step by Step Fix
Step 1 — Check Time Sync on Your Device Two-factor authentication codes are time-sensitive. If your device’s clock is even slightly out of sync, the codes will be rejected. On Windows, go to Settings, then Time and Language, and enable Set time automatically. On Mac, go to System Settings, then General, then Date and Time, and enable Set time and date automatically.
Step 2 — Use Backup Codes When you set up two-factor authentication on Slack, backup codes were provided. Use one of these backup codes to log in if your primary authentication method is not working.
Step 3 — Contact Workspace Admin If you are locked out of a workspace due to 2FA issues and have no backup codes, ask your workspace admin to disable 2FA on your account temporarily so you can log in and reconfigure it.
Step 4 — Contact Slack Support If you are the workspace owner and are locked out, contact Slack support directly at slack.com/help. Provide account verification details and they will assist with account recovery.
Slack Screen Sharing Not Working
Screen sharing in Slack calls is useful for remote collaboration but frequently encounters permission or performance issues.
Step by Step Fix
Step 1 — Grant Screen Recording Permission
On Mac:
- Go to System Settings, then Privacy and Security, then Screen Recording
- Make sure Slack is listed and the toggle is enabled
- Restart Slack after granting permission — Mac requires an app restart for screen recording permissions to take effect
On Windows:
- Screen sharing does not require a specific permission beyond the standard Slack call setup
- If screen sharing fails on Windows, check whether a VPN or firewall is blocking the connection
Step 2 — Stop Sharing and Reshare If the screen share freezes mid-call, stop sharing, wait 10 seconds, and start sharing again. This resolves most temporary freezing issues.
Step 3 — Share a Specific Window Instead of Full Screen Sharing a specific application window uses less bandwidth and processing power than sharing the entire screen. In the screen share dialog, select the individual application window rather than your full desktop.
Step 4 — Lower Video Quality If screen sharing is laggy or choppy, lower the video quality in Slack’s audio and video preferences. Reducing resolution decreases the bandwidth requirement and smooths out performance on slower connections.
Step 5 — Use an Alternative If Slack screen sharing consistently underperforms, consider using Google Meet or Zoom for screen sharing while keeping Slack for messaging. Both platforms handle screen sharing more reliably for most users.
General Slack Troubleshooting Checklist
Before deep troubleshooting any Slack issue, run through this checklist first — it resolves the majority of common problems:
- Check status.slack.com for active incidents
- Confirm internet connection is stable
- Force quit and restart Slack
- Clear Slack cache
- Check for and install available updates
- Confirm notification permissions in operating system settings
- Log out and log back in to refresh the session
- Reinstall Slack if the issue persists after all other steps
Final Thoughts
Slack problems are rarely permanent. The majority of issues — loading failures, notification gaps, call audio problems, and performance slowdowns — respond to a consistent set of fixes: clearing cache, checking permissions, updating the app, and verifying server status before assuming the problem is local.
The key habit to build is checking status.slack.com before spending time troubleshooting locally. If Slack is experiencing a service incident, no local fix will resolve it — and knowing that saves time and frustration.
Keep Slack updated, clear the cache periodically, and maintain correct operating system permissions for notifications, microphone, camera, and screen recording. Most users who do these things consistently rarely encounter serious problems.
