When trying to open a file downloaded from FYIan error similar to the following is displayed:
"Adobe Acrobat could not open (filename) because it is either not a supported file type or because the file has been damaged (for example, it was sent as an email attachment and wasn't correctly decoded).
This error could be experienced with emails (.eml) or other types.
It's likely the default program used to open the file type is not the correct program. For example, .eml files are designed to be opened by a mail program, like Outlook. If it has been set to open with Adobe Acrobat, the error will be displayed as Adobe cannot open these file types.
You will need to change the default program in Windows used to open the file. Windows has the ability to "Choose defaults by file type" so you can set the correct behaviour.
For example, the recommended application for .eml is Microsoft Outlook.
For step-by-step instructions refer to the Microsoft article Change default programs in Windows.