Users frequently report an issue where CorelDRAW (.CDR) files, when sent through WhatsApp, are automatically renamed and displayed as .ZIP files on the recipient’s device.
Although the file opens correctly after renaming it back to .cdr, this behavior causes confusion, support tickets, and doubts about file corruption.
This article explains why this happens, confirms data integrity, and provides step-by-step solutions and best practices to avoid the issue.
Native design file format used by CorelDRAW
Stores vector graphics, layers, fonts, effects, and metadata
Internally uses a compressed container structure
Supports document sharing up to size limits
Uses file signature detection rather than just file extensions
Optimizes and reclassifies unknown file types
A .CDR file is technically a compressed archive (similar to ZIP containers).
When WhatsApp encounters a file type it does not explicitly whitelist:
WhatsApp scans the binary file signature
Detects ZIP-like compression headers
Assumes the file is a ZIP archive
Renames the extension to .zip for compatibility
Important:
This is a classification issue, not file corruption.
| Behavior | Explanation |
|---|---|
File extension changes to .zip | WhatsApp auto-detection logic |
File opens after renaming to .cdr | Data integrity is intact |
| Happens mostly on Android | Android file manager relies on extension |
| WhatsApp Desktop works better | Less aggressive detection |
Sender side
Right-click the .cdr file
Select Send to → Compressed (zipped) folder
Send the .zip file via WhatsApp
Receiver side
Download the ZIP file
Extract contents
Open the .cdr file normally
Rename the file before attaching:
design.cdr → design.cdr_.zip
Receiver renames it back:
Send the file from WhatsApp Web or Desktop
File extension is usually preserved
Recommended for professional environments
Upload to:
Google Drive
OneDrive
Dropbox
Share the download link instead of the file.
| Issue | Fix |
|---|---|
| Client thinks file is corrupted | Rename back to .cdr |
| ZIP opens but shows unknown file | Extract and open in CorelDRAW |
| WhatsApp auto-renames again | Use cloud link or manual ZIP |
| Android cannot preview file | Expected behavior |
WhatsApp performs content scanning to prevent malware
Unknown extensions are treated cautiously
Renaming is a protective behavior, not malicious
ZIP containers reduce false positives
Always ZIP professional design files
Inform recipients in advance
Prefer cloud links for client delivery
Avoid sending raw .cdr files via mobile
Maintain version control when sharing assets
When WhatsApp renames a .CDR file to .ZIP, it is performing automated file-type detection based on internal structure.
The file remains fully intact and safe.
Using ZIP packaging or cloud storage ensures consistent delivery, avoids confusion, and aligns with professional IT and design workflows.
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