Why REST API File Submission with downloadfrom Header Fails When Using RAMDISK for Temp Directory?
Check Your Version: This article applies to all MetaDefender Core releases deployed on Windows and Linux systems after 5.11.1.
Issue:
When configuring a RAMDISK as the temporary directory using IMDisk, file submissions through the browser interface function correctly; however, submissions via the REST API fail due to issues with the downloadfrom header.
Error Details:
The following error is logged:
[WARNING] 2025.11.03 20:50:22.994: (common.workflow) Workflow block ended with exception, block='ErrorRestResponse', workflow_id='', error='Cannot send message to Frontend' [msgid: 97]
You may encounter the message 'Cannot send message to Frontend' in core.log, while the REST API request returns an error: “err”: “File download rejected due to insufficient disk space”.
Resolution:
Until a fix is available, consider using a physical disk path for the temporary directory instead of a RAMDISK when submitting files via the REST API with the downloadfrom header.
Support:
If Further Assistance is required, please proceed to log a support case or chatting with our support engineer.