I just wanted to report a bug in FlasgGot 184.108.40.206 with Firefox 51.0.1 (latest) with the option "download all files" (my FlashGot is in French so this is my guess for English).
Whatever the download manager chosen (even integrated to navigator), the Excel files are corrupted :the content of the file is actually HTML code instead of Excel code.
The sites from which I want to download files are in HTTPS and need authentication.
I tried different things that did not solve the issue :
- active HTTP authentication
- delete "mimeTypes.rdf" from my profile so that Firefox re-generates it.
This solved the issue : switching from "download all files" to specific "Extensions".
That's all !