Galaxy phone PDF downloads a .bin

[Art Ream]

Why does every download to my phone and Samsung running android get chnaged to a 'dot. BIN' extension then I cannot open them even renaming results in file name.pdf.bin

How do I fix this?

 

[Rukbat]

I don't know why it's happening (it doesn't on my Note 3 - I just downloaded a pdf with no problem), but you can copy the file to a computer, rename it there, then copy the pdf file back to the phone.