The short answer
First distinguish a failed send from an attachment that was sent but has no preview. For size errors, use the limit currently shown for your account and channel. For failures in one channel, check attachment permissions. If a tiny harmless image also fails, compare the app and browser under the same conditions. Respect safety blocks instead of trying to get around them.
Different symptom or still not fixed? Find the next check →Key facts
- Start here
- Record the exact error and whether the attachment exists in message history.
- Size check
- Compare the local source file with the current on-screen limit, before automatic compression.
- Controlled test
- One harmless JPEG under 100 KB, only in the same private channel where testing is permitted. This is a test size, not an upload limit.
- Stop condition
- A content or malware warning means stop sending that file and follow the warning.
Find your symptom
Start with your symptom. Skip steps that do not apply to your setup.
| What you see | What to check | Go to |
|---|---|---|
| A file-size error appears as soon as you select the file | Compare the local source size with the limit shown for this account and channel. | Step 2 |
| Text sends, but even a tiny image cannot be attached in this channel | Text permission does not establish attachment permission. Ask an administrator to check the effective channel permissions. | Step 3 |
| Text also fails, or the composer/attachment action is unavailable | Check read-only or posting restrictions, including thread-specific send permission. | Step 3 |
| The control image sends, but the original file fails | Check size, then whether the original opens locally. This points toward a file-specific issue, not proven corruption. | Step 4 |
| The attachment exists and your own file downloads, but there is no preview | The upload succeeded. Check format and display settings rather than repeatedly resending. | Step 4 |
| Even the tiny control image stalls during upload | Compare the same file, account and permitted channel in the app and browser. | Step 5 |
| A sensitive-content, safety or malware warning appears | Stop retrying and record the warning. Do not change extensions or routes to bypass it. | Step 6 |
Fixes, in order
Continue this issue
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Step 1｜Locate the failure and prepare a safe control file
File selection, a failed send and a missing preview are different stages. Record what happened without repeatedly posting private images or logs.
Time: 2–3 minutes · Risk: low
- Record the error text, time and time zone, device, file type and file size. Go directly to Step 6 for a safety warning or Step 2 for a size error.
- If the attachment remains in message history and you can download your own file, treat it as sent and use Step 4. A pending or failed-send indicator instead calls for upload troubleshooting.
- Create a small solid-color JPEG locally in an image editor, with no personal information in the image or filename. Under 100 KB is a suggested control size, not a Discord limit.
- Only if the original destination is private and test posts are permitted, send that one file once using the same account and channel. Success points to Steps 2 and 4 for the original file; failure points to Steps 3 and 5.
Do not post tests in public servers or restricted channels. If testing in the affected channel is not allowed, ask an administrator for a private test location; success elsewhere does not prove permission in the original channel. Never use screenshots, private conversations or game logs as control files.
Step 2｜Compare the current limit with the file before compression
As checked on October 3, 2026, the September 30 attachment FAQ lists free 20 MB, Basic 50 MB and Nitro up to 1 GB. The June 11 image guide still says 10 MB. Experiments are explicitly documented, so these are dated descriptions rather than one universal cap.
Time: 2–5 minutes · Risk: low
- Read the limit displayed in the upload or error screen for this account and destination channel. If it differs from an article, use the current screen instead of repeatedly trying against an assumed number.
- Read the source file size in your device’s file information or properties. The attachment FAQ describes a pre-compression check, so mobile quality settings or automatic compression are not a guaranteed way past a size error.
- If it is too large, preserve the original and edit a copy locally: lower image dimensions/quality or trim unnecessary video. Check that the saved copy is comfortably below the displayed limit.
- Confirm the content and destination are appropriate, then try the copy once. If the same error persists well below the limit, keep the error text and use Steps 5 and 6. Buying Nitro is not a prerequisite for diagnosis.
The September 29 Nitro guide also lists Basic 50 MB and Nitro up to 1 GB, but retains an older free-tier explanation mentioning 10 MB. Later changes remain possible. Do not upload private images or logs to online compressors/converters, and do not overwrite the original.
Step 3｜Check effective attachment permission in this channel
Sending text and attaching files are separate permissions. Ask an administrator to check what actually applies in this channel, rather than relying only on a server role.
Time: 2–3 minutes; administrator response may take longer · Risk: low
- Use existing posts and the composer’s notice to establish whether ordinary text can be sent. An unavailable composer is not a file-size problem.
- If text works but the small control image does not, ask an administrator to check the effective Attach Files permission for this channel.
- For a normal channel, also check message-sending permission; for a thread, check permission to send messages in threads. Mention any channel/member overrides and visible posting restriction.
- Only after an administrator authorizes the test and fixes any permission problem, retry the same small image from Step 1. If attachments are intentionally disallowed, respect that rule and stop here.
Do not bypass server restrictions with another account, a DM or an external service. Embed Links controls link previews and is separate from Attach Files; changing it does not remove an attachment restriction.
Step 4｜Separate an original-file problem from a preview problem
A downloadable attachment without an inline picture is different from a failed upload. A file being attachable does not guarantee that Discord can display or play it inline.
Time: 3–5 minutes · Risk: low
- Open the original locally in a suitable app. If it cannot open, is empty or is still being saved, finish saving it or obtain a valid copy. Renaming an extension does not convert the contents.
- If the original image opens but only that image fails, preserve it and export a separate JPEG locally. Recheck size and whether the content is safe to share, then compare in the same permitted location.
- If message history shows an attachment filename and download action, check whether your own harmless file downloads. A PDF can be attached without an image-style preview; text previews also have separate rules. No preview alone does not establish a failed send.
- If your own attachment downloads but images are not displayed, inspect image/preview options under the user settings’ Chat section. Record any value before changing it and restore it if the change does not help. Leave safety filters and channel permissions alone.
Do not open an unknown sender’s file as a test. A video extension alone does not establish playback support. A successful control image does not prove the original is corrupt or that its format is unsupported.
Step 5｜Compare the app and browser without changing other conditions
Use this after a tiny control file fails and no size or posting-permission problem was found. Changing the destination and file as well would make the result hard to interpret.
Time: 3–5 minutes · Risk: low
- Check Discord Status for an ongoing incident matching the time of the failure. If relevant, stop repeated sends and retry the same small image after recovery. An empty incident list does not prove your device is at fault.
- On a PC, compare the official web client at discord.com/app with the app on that same device. Use the same account, private permitted channel and control image, with one attempt in each. Verify the official domain if sign-in is required.
- If only one client works, fully close and reopen the failing one, apply normal official updates and retest once. Warn call participants before closing Discord. The working client can be used temporarily within the channel’s rules.
- If both fail, check whether ordinary websites load. If needed, compare on another trusted network you are allowed to use, keeping the other conditions fixed. Comparing a mobile device with a PC also changes the device, so it cannot isolate the app alone.
Do not use a different network or VPN to evade workplace or school restrictions. Leave antivirus and firewall protection enabled and ask the administrator. A full cache wipe or reinstall is not needed before these results are available.
Step 6｜Respect safety warnings and send only necessary support details
A content block is different from a connection failure. If you suspect a false positive, follow the displayed guidance instead of repeatedly modifying or redistributing the blocked file.
Time: 5 minutes to prepare a report · Risk: low
- Stop sending a file flagged for inappropriate content or safety. Do not crop it, rename its extension, encrypt it in a ZIP or use another account to evade inspection.
- Do not run or resend a file flagged as malware. Check with the source or administrator without adding a security exclusion. Ask the server administrator about permissions, or official Discord Support about upload problems or suspected false positives.
- Prepare the exact error, time and time zone, OS and app/browser versions, file type and size, on-screen limit and same-control-file comparison results. Do not attach the original file by default.
- If a screenshot is needed, keep the original locally and edit a copy on your device. Cover tokens, authentication codes, email addresses, usernames and private conversations with opaque redaction, then reopen the exported image to check for anything left visible.
Use the official support form in Sources. Never send sign-in QR codes, passwords or tokens. Do not post private logs or original attachments to public channels or online converters; give the official private support channel only what it needs.
Avoid
- Do not turn dated 10 MB, 20 MB or 500 MB figures into a universal limit; use the current account/channel display.
- Do not overwrite originals or send private files to online compression/conversion tools.
- Do not bypass attachment restrictions or safety blocks using DMs, other accounts, extension changes or encrypted archives.
- Do not disable security software, evade managed-network rules, or start with a full cache wipe/reinstall.
Important cautions
- Control tests belong only in the same private channel where posting and testing are permitted. If another location is needed, its success does not establish permission in the original channel.
- Do not test with private screenshots, conversations or logs, and do not open unknown attachments.
- Before sharing a screenshot, preserve the original, redact a local copy, and inspect the exported result for tokens, codes, email addresses, usernames and private chat.
- If unresolved, report the error, time zone, versions, type/size, current limit and comparison results through official private support. Do not include the original file or raw logs automatically.
FAQ
Is the free limit 10 MB or 20 MB? Is Nitro still 500 MB?
The attachment FAQ checked on October 3, 2026 was updated September 30 and lists free 20 MB, Basic 50 MB and Nitro up to 1 GB. The June 11 image guide still mentions 10 MB. These official descriptions conflict and experiments are documented. Do not rely on older 10 MB or 500 MB figures as fixed limits: use the current display for your account and channel.
Why does mobile still show a size error after I lower upload quality?
The attachment FAQ describes checking size before compression. Preserve the original, export a smaller copy locally and check that copy’s size rather than relying on Discord’s quality setting. Private images or logs do not need to go through an online compressor.
Text sends but images do not. Does that prove a permission problem?
No, but it is a possibility: text sending and file attachment are separate permissions. If a tiny harmless image also fails in the same private permitted channel, ask an administrator to check effective Attach Files permission, then compare clients.
Does a missing PDF or video preview mean the upload failed?
No. If the attachment exists in history and your own safe file downloads, separate delivery from preview behavior. Format, video encoding and display settings can affect inline viewing or playback. Renaming a file extension does not convert it.
If the tiny image works, is the original file corrupt?
That result alone cannot tell you. It narrows attention to size, save state and format. Check the current limit and whether the file opens locally; for an image, preserve the original and compare a separately exported JPEG. Do not modify and resend an original that triggered a safety warning.
Should I disable a filter, ZIP the file or use another account?
Do not use these methods to evade a safety block or server attachment rule. Follow the warning, ask the administrator about permissions, and use official support for suspected false positives. Do not run or redistribute a malware-flagged file.
Can I send my full game log or Discord screenshot to support?
Start with the error, time, versions, file type/size and test results. If a screenshot is necessary, edit a local copy, cover tokens, codes, email addresses, usernames and private conversations, then inspect the exported image. Keep the original private and share only relevant details through official private support.
Sources
Based on official sources checked on October 3, 2026. The comparison sequence is editorial troubleshooting guidance, not a claim of hands-on testing across devices or accounts. Official limit descriptions are inconsistent and experiments are documented; use your current in-app account/channel limit. All linked sources below are in English.
Discord: File Attachments FAQ (updated September 30, 2026; sizes, pre-compression checks and display)Discord: Uploading images and GIFs (updated June 11, 2026; older limit remains)Discord: Nitro and Nitro Basic (updated September 29, 2026; some older text remains)Discord developer documentation: message, attachment and thread permissionsDiscord: Permissions overview (attachments versus link previews)Discord: File Preview (text previews)Discord: Safer Messaging (image filters)Discord: Troubleshooting and reporting bugsDiscord Status: official service incidentsDiscord: official support request formDiscord (Japanese)Japanese version of this page