File download problem

[cholewak]

When downloading files Blob uses FileReader to convert the file to base64. When the files are not yet written anywhere. They are still in memory. It executes
reader.readAsDataURL(blob); and at that point I get an error in the devtools console. with reader.onerror();

NotReadableError: The requested file could not be read, typically due to permission problems that have occurred after a reference to a file was acquired.

Only then does it write the file. via a shared method from the desktop application.

The implementation works on multiple machines. This is just one exception.

Do you have any ideas on how to solve the problem? Or how to debug it?