Files Not Uploading
Slack Slack
Severity: ModerateWhat Does This Error Mean?
Slack file uploads fail when the file is too large or your connection is too slow. Free workspaces have tighter limits than paid ones. Sharing a cloud link is often faster than a direct upload.
Affected Models
- Slack on Windows
- Slack on Mac
- Slack on Android
- Slack on iPhone
Common Causes
- File exceeds Slack's size limit (1 GB max on paid plans, much less on free)
- Internet connection is too slow to handle a large upload
- Workspace storage quota has been reached
- Workspace admin has restricted certain file types
- Slack app is outdated and needs an update
How to Fix It
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Check the file size before uploading. Slack allows up to 1 GB per file on paid plans.
Free workspaces have a total storage cap of 5 GB shared across the whole workspace — not per file.
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Test your internet speed at fast.com — uploads need a stable connection.
A slow or dropping connection will cause large uploads to fail or time out mid-transfer.
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Compress the file or reduce its size before uploading.
For videos, use a tool like HandBrake. For images, use TinyPNG. For documents, save as a compressed PDF.
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Upload the file to Google Drive or Dropbox, then paste the share link into Slack instead.
This avoids Slack's storage limits entirely and is often faster for large files.
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Update Slack to the latest version via the app store or slack.com/downloads.
Outdated Slack versions sometimes have upload bugs that are fixed in newer releases.
When to Call a Professional
This is a software or storage issue. All fixes can be done without a technician.
Frequently Asked Questions
What is Slack's file size limit?
Paid plans allow up to 1 GB per individual file. Free workspaces share a 5 GB storage pool — once it's full, uploads fail for everyone.
Can my workspace admin stop me from uploading certain file types?
Yes. Workspace admins can restrict file types for security reasons. Contact your Slack admin if your uploads are blocked but the file is within the size limit.
Why does my file upload get stuck at 0%?
A stuck upload almost always means a connection problem. Check your internet, try switching from Wi-Fi to a wired connection, then retry the upload.