You upload a PDF to Notion and it syncs instantly. But when you attach a .psd, .ai, or .zip file, the upload bar stalls or shows a sync error. This selective failure is not random — it is caused by Notion’s file size and format limitations that apply differently across attachment types. This article explains the root cause of type-specific sync failures and provides exact steps to fix and avoid them.
Key Takeaways: Fix Notion Sync Failures for Specific File Types
- File size limit per attachment: 5 MB on Free plan and 5 GB on Plus or higher — files above the limit will not sync regardless of type
- Unsupported file types: Notion blocks .exe, .dll, .msi, .bat, .cmd, .scr, .ps1, .vbs, .jar, and .app — these cause an instant sync failure
- Compressed or binary files: .zip, .rar, .7z, .psd, .ai, and .dmg often fail due to Notion’s internal file processing limits on binary content
Why Notion Rejects Certain File Attachments
Notion uses a cloud-based file storage system that processes each uploaded file through a content inspection pipeline. This pipeline checks three things: file extension, file size, and whether the file contains executable code or binary data that could pose a security risk.
File Extension Blacklist
Notion maintains a list of blocked file extensions that cannot be uploaded under any condition. These include .exe, .dll, .msi, .bat, .cmd, .scr, .ps1, .vbs, .jar, and .app. If you attempt to attach a file with one of these extensions, Notion will reject it immediately and show a sync error. This is a security measure to prevent malware from being distributed through shared workspaces.
Binary and Compressed File Processing Limits
File types like .zip, .rar, .7z, .psd, .ai, .dmg, and .iso contain binary data or compressed archives. Notion’s file processing system may time out or fail when trying to generate a preview thumbnail for these files. The sync process depends on the thumbnail generation completing successfully. When the thumbnail fails, the entire upload is marked as failed even though the raw file was fully transferred. This is the most common cause of type-specific sync failures.
File Size Threshold Differences
Notion applies a 5 MB file size limit for attachments on the Free plan. On Plus, Business, and Enterprise plans, the limit is 5 GB per file. However, some file types such as large .zip archives or high-resolution .psd files may exceed the limit and fail silently. The error message often does not specify that the file is too large — it simply says sync failed.
Steps to Fix Sync Failures for Specific File Types
- Check the file extension against the blocked list
Open File Explorer on Windows or Finder on macOS. Right-click the file and select Properties or Get Info. Look at the file extension after the dot. If it matches .exe, .dll, .msi, .bat, .cmd, .scr, .ps1, .vbs, .jar, or .app, you cannot upload it to Notion. Rename the file to change the extension — Notion will still block it because it inspects the file header, not just the extension. You must compress the file into a .zip archive or use a cloud storage service like Google Drive or Dropbox and paste the share link into Notion. - Check the file size against your plan limit
Right-click the file and select Properties. Note the Size value. If you are on the Free plan, any file larger than 5 MB will fail. On Plus or higher, files larger than 5 GB will fail. Reduce the file size by compressing images or splitting archives. For .psd files, flatten layers and save as a smaller .jpg before uploading. - Compress unsupported binary files into a .zip archive
Select the file in File Explorer. Right-click and choose Send to > Compressed (zipped) folder. This creates a .zip file. Upload the .zip to Notion instead of the original .psd, .ai, or .dmg file. The .zip format reduces the chance of thumbnail processing failure because Notion does not attempt to generate a preview for archive files. - Upload from a different browser or desktop app
Open Notion in Google Chrome or Microsoft Edge. If you are using the Notion desktop app, try the web version instead. Browser uploads sometimes bypass processing errors that occur in the desktop app. Clear the browser cache before uploading: press Ctrl+Shift+Delete, select Cached images and files, and click Clear data. - Use an external cloud storage link instead of a direct attachment
Upload the problematic file to Google Drive, Dropbox, or OneDrive. Copy the share link. In Notion, type /embed and paste the link. This bypasses Notion’s file processing entirely and allows any file type to be accessed from within the page.
If Notion Still Shows Sync Errors After These Fixes
File upload bar stays at 0% for more than 30 seconds
This usually indicates a network issue rather than a file type problem. Restart your router. Temporarily disable any VPN or proxy service. Test your upload speed at speedtest.net — you need at least 5 Mbps upload speed for files larger than 100 MB. If the network is stable, the file may be blocked by your organization’s firewall. Contact your IT team to allow uploads to notion.so.
File shows as uploaded but the preview is missing
The file may have been uploaded successfully but Notion could not generate a thumbnail. The file is still accessible. Click the file name to download it. If you need a preview, upload a separate screenshot of the file content and place it next to the attachment.
Sync fails only on mobile app but works on desktop
The Notion mobile app has stricter file size limits than the desktop or web version. On iOS and Android, the maximum file size for uploads is 30 MB regardless of your plan. Upload large files from a computer instead.
Notion File Attachment Limits by Plan
| Item | Free Plan | Plus / Business / Enterprise |
|---|---|---|
| Maximum file size per attachment | 5 MB | 5 GB |
| Blocked file extensions | .exe, .dll, .msi, .bat, .cmd, .scr, .ps1, .vbs, .jar, .app | Same as Free |
| Binary file preview support | Limited — .psd, .ai, .dmg may fail | Limited — same as Free |
| Mobile app maximum upload size | 30 MB | 30 MB |
| External link embedding | Supported — bypasses all file limits | Supported |
Notion sync fails for specific file attachment types because of extension blacklists, binary preview processing limits, and plan-based size caps. By checking the file extension and size first, compressing binary files into .zip archives, or switching to an external cloud storage link, you can upload any file type to Notion without sync errors. For files that still fail, use the Notion web version in Chrome or Edge and disable any active VPN before uploading.