Error File does not exist when uploaded through Flow App

Hi Folks,

Almost weekend and we got a bit of a strange situation. We have a Flow App that is being used by most of our users. They upload a GeoJSON and select if they want Aerial Imagery or Topographic Background. The result is a generated PDF Map.

This process works fine for all but one user. When this user uploads a GeoJSON we see in the log the following error:

90	2026-8-7 15:44:02 | GEOJSON Reader: The file 'C:\ProgramData\Safe Software\FMEFlow\resources\system\temp\upload\[Projectname]\[Workspacename]\auth-user\[USERNAME]\508a819f-ee99-bb88-9785-82b3a169082e\[GeoJSONname]' does not exist
91	2026-8-7 15:44:02 | An error has occurred. Check the logfile above for details

If any other user uses the same GeoJSON file the process works fine.

We checked the following:

• User rights are identical
• The GeoJSON is valid (others can use it fine)
• We checked the timestamps in the DataUpload log with the Job Log and the file is uploaded before it's read.
• We checked with the user where it doesnt work if they do anything different then users where it works and they use an identical process for uploading the file (drag from File Explorer)

Anybody have any idea what could cause this?