Soldato
Well, had an customer phone in with a problem the other day and people were having trouble diagnosing it. So over to me 
The user was trying to attach a PDF document to upload, and the result of trying to attach it, was it failing the mime type check. (i.e. Our code is rejecting the file as it can't determine that it's a PDF file.)
As I don't have any traces to go on, the most reasonable explanation that I can come up with is that Firefox passing a malformed or incorrect mime type. Doing some checking resulted in me finding this: http://techblog.procurios.nl/k/news/view/15872/14863/mimetype-corruption-in-firefox.html
Basically it seems the problem is the RDF file for a particular profile (The one currently used by Firefox) as associated something wrong (in this case a PDF file), and so is passing the wrong mime type.
To keep it simple for the customer, I have suggested he reset his firefox profile so it will hopefully clean this out (Following some mozilla instructions). Failing that, he can use firefox.exe -P from the command line (without firefox running) and create or delete a profile, which should also get around the problem.
Interestingly, this dynamic assignment problem is actually a feature of Firefox rather than a bug (and a new one to me as I we don't normally use Firefox).
Just thought some people might be interested
The user was trying to attach a PDF document to upload, and the result of trying to attach it, was it failing the mime type check. (i.e. Our code is rejecting the file as it can't determine that it's a PDF file.)
As I don't have any traces to go on, the most reasonable explanation that I can come up with is that Firefox passing a malformed or incorrect mime type. Doing some checking resulted in me finding this: http://techblog.procurios.nl/k/news/view/15872/14863/mimetype-corruption-in-firefox.html
Basically it seems the problem is the RDF file for a particular profile (The one currently used by Firefox) as associated something wrong (in this case a PDF file), and so is passing the wrong mime type.
To keep it simple for the customer, I have suggested he reset his firefox profile so it will hopefully clean this out (Following some mozilla instructions). Failing that, he can use firefox.exe -P from the command line (without firefox running) and create or delete a profile, which should also get around the problem.
Interestingly, this dynamic assignment problem is actually a feature of Firefox rather than a bug (and a new one to me as I we don't normally use Firefox).
Just thought some people might be interested