Unable to Open Files Which is Downloaded From Web

From today morning I am unable to open any file which I am downloading from this site and excel simply saying a message stating that the file is corrupted, no clue what caused excel to react like this.

Even I am already having the download location folder in the Trusted Location and still digging excel for the cause of this problem.

Any thoughts will be very much helpful.

As alternative solution I had saved the file from another browser (Opera to Mozilla) and this is working fine.

Does anyone is facing the same problem whoever using the Opera browser and is it occurring with any other browsers too?

Addendum:-

The root cause of this problem is by default Opera browser is saving all files in xlsm format because of the tick mark made in Remember The Choice while downloading the file.

So in opera browser memory it made all unknown files (according to opera browser xlsm/xlsx/xlsb are unknown file types) so whatever the file which is not in opera library will be treated as unknown file type and due to the option made above (Remember The Choice) opera keep on saving all the unknown file types as .xlsm which caused this problem.

To remove this from opera memory:-
Settings>>Preferences>>Advanced>>Download>>Select Unknown (Nearby You can see the default file type(extension) assigned by Opera for saving Unknown File types)>>Delete>>Ok

Problem solved