Embedded .txt files fail to open in Word documents (v9.4.0.129 / Win11)

Do you want to: Report a bug

Description:
When opening an existing .docx file that already contains an embedded .txt attachment, double-clicking the embedded text object fails to open it. The issue is specifically about accessing pre-existing embedded .txt files, not about inserting new ones.

Steps to reproduce:

  1. Open ONLYOFFICE Document Editor (Desktop or Web).

  2. Open an existing .docx file that already contains an embedded .txt attachment.

  3. Double-click the embedded .txt object within the document.

  4. Result: The file fails to open / displays an error / remains blank. (Please specify which behavior you see)

Expected result:
The existing embedded .txt attachment should open correctly when double-clicked.

OS version: Windows 11 (24H2)
App version: 9.4.0.129
Downloaded from: ONLYOFFICE website
Installation guide used: Official Desktop Editors installer from ONLYOFFICE desktop and mobile apps | ONLYOFFICE