Media upload is too large

When you attach media during Create, Choose media may reject a file and show a size error. Slack names the file and states it exceeds the 10 MB per-file upload limit. The attachment does not appear in the Create modal until you pick a source that fits the limit or use a different ingestion path.

You may see this only during direct upload in Create, while the same file could still work after you add it through Media Library or a supported link.

Symptoms

• Choose media shows an error that a named file exceeds the 10 MB limit.
• Direct file upload in Create fails, but you expect the asset to work on the social platform.
• Carousel setup fails when one slide is over the per-file cap, even if other slides are small.
• Upload succeeds in Choose media, but preview or publish later warns about format or size (a platform limit, not the upload cap).

Checks

Confirm where the failure happens:

1. Read the full error in Choose media. Note the filename and the 10 MB limit in the message.
2. Confirm you are uploading in Choose media during Create rather than adding the file in Media Library first.
3. Check file size on your computer. High-resolution video and uncompressed images often exceed 10 MB.
4. For carousels, verify each direct-upload slide stays under 10 MB.
5. If the error appears only at preview or publish, open Platform support for platform-specific caps.

Likely causes:

• The file is larger than the 10 MB direct-upload limit in Choose media.
• A large master was selected for direct upload instead of library ingestion.
• A file that social platforms accept still must enter Slash Social through the asset library path when it is over the upload cap.

Fixes

1. Use Media Library for larger files. Open Media Library from Create or run /social and open the library from there. Upload the file, wait for ingestion to finish, then return to Create and select the asset in Choose media.
2. Use a direct URL when the file is hosted elsewhere and Choose media accepts link-based media for your format.
3. Compress or export a smaller version when you only need a draft and can keep the full-resolution master in the library.
4. Split carousel sources so each slide stays under the per-file upload cap when uploading directly.

Platform publishing limits may still apply after upload. See Platform support when a file attaches successfully but preview or publish warns about format or size.

Confirm the fix

Choose media accepts the source (library asset, link, or smaller upload). The Create modal shows the attachment without a size error, and you can save or continue editing.

Prevent it next time

• Upload large masters to Media Library once, then reuse library assets in Create. See Media, assets, and the content library.
• Export web-ready sizes before direct upload when you do not need the full master in the post.
• Review format and size rules in Platform accounts and format support before you schedule.

Contact support

Contact support when:

• A file clearly below 10 MB still triggers the size error in Choose media.
• Library ingestion fails repeatedly for the same asset.

Send the workspace, brand, file type, approximate size, and whether you used direct upload, a URL, or Media Library. For step-by-step workflows, see Manage the Asset Library, Choose media for a post, and Media is required before saving or previewing.