2 Excel VBA macros

Hi, I would need an Excel VBA macro. It needs to be quick (running for less than 1 min), and the spreadsheet can have many rows (100k+) As you can see the attached excel file has header in row 2 and some extra headers in random rows, First thing the macro should is getting rid of any extra header rows, i.e delete them (delete in a way that no blank row appears). The macro needs to be quick so looping through the spreadsheet row by row might not be a good idea. When this is done the macro should do the following. Identify the last column which still has some data, in this case column H - but obviously this can be different. (if you need a max number columns to be checked, let us say max is 20, that is how many columns you need check) Then the macro should : 1. leave column A as it is 2. replace the content of column B with a string that joins together all columns from B to the last that still has data (in this case H) 3. delete the data from column C onwards (except the headers) You can see the desired result in tab "Desired result". However please note that the macro should not create a new tab, all the actions should be performed on the original tab (Tab "Data") Please can you provide explanation of the code within the macro.