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"This format cannot be attached" is displayed

2026-08-22 17:11:50 UTC 2026-10-07 09:30:30 UTC

When you attach a file to an AI Chat, the following messages may appear.

  • This format cannot be attached: (File name) (Supported formats: JPEG, PNG, GIF, WebP, PDF, BPMN)
  • Cannot attach because an unsupported format is included: (File name) (Supported formats: JPEG, PNG, GIF, WebP, PDF, BPMN)
  • The file size of (File name) exceeds the limit ((limit) MB)
  • The image size of (File name) is too large (width and height must each be within 8000px)
  • BPMN files can be attached up to a total of 0.5MB per message sent
  • Failed to read the attached file

Cause

Files that can be attached to AI Chat are subject to the following restrictions.

  • Images...JPEG / PNG / GIF / WebP, up to 3MB per file, up to 8000px each in width and height
  • PDF...up to 10MB per file
  • BPMN....bpmn / .bpmndi, up to 0.5MB per file, up to a total of 0.5MB per message sent

Only the type of file selected from the [+] menu can be chosen; however, if you select "All Files" in the File Selection dialog, unsupported formats can also be selected. In that case, the file will not be attached and this message will appear.

When multiple files are dragged and dropped at once, if even one file in an unsupported format is included, none of the files will be attached.
In this case, the message "Cannot attach because an unsupported format is included" will be displayed.

Resolution

Please convert the file to a supported format before attaching it. Excel or Word documents can be attached by exporting them as PDF.

For large images or images with a width or height exceeding 8000px, please reduce the resolution or compile them into a PDF before attaching.

If a BPMN file exceeds the limit, please split the process into separate exports or split the attachments across multiple messages.

Related

Tell me about AI Agent
https://help.process.teachme.jp/hc/en-us/articles/61437450294169