Excel Cannot Open The File

Hi guys so i am currently getting an error from a file i was using today.. it reads as follows.

" Excel cannot open the file 'Pickrates.xlsm' because the file format or file extension is not valid. Verify that the file has not been corrupted and that the file extension matches the format of the file."

I've tried a few options and one being changing the file name type to .xlsx but it did not work (was a copied version so i didn't lose the file if it corrupted by changing the file type).

Any other suggestions? i can't open the file at all and would really like to get the information on there off as its very important.

Don't believe i can upload the file as its 4,712 KB

Thanks

Tried them, Doesn't work :\