Excel file taking 3 minutes to open

Hi All,

I have a macro enabled excel file full of formatting and dropdown. The initial version of the file was of 18 MB but was opening smoothly. There cane an enhancements where some more macros were added to the file. I reduced the size to 12 MB after removing the extra data. But now the 12 MB file is taking almost 3 minutes to open.

Please suggest how to check where is it taking time to open and how can this be reduced to less than one minute ?