Develop Macros In Their Own Workbook

Excel includes VBA as a powerful programming language that you can use to develop all sorts of macros. It is not unusual, as you are developing macros, to go through many iterations and make wholesale changes to your macros. You may want to keep in mind, however, that doing so can cause problems in your worksheets.

As you make changes to macros, adding and removing code, the actual file used to store the macros (the workbook) can get quite fragmented. It seems that internally the macros are stored in blocks, and much like a disk drive, the blocks can become "non-contiguous" over time. (This happens only through editing, not through use of the macros themselves.) Some readers have reported that there are times the fragmentation can get so bad that the macros may fail or the workbook become unusable.

The solution to this potential problem is to do your macro development in a different workbook than the one that will eventually hold the macros. Thus, when the macro is transferred to its final home, it will be transferred as a contiguous block, rather than being fragmented.

If you want to make sure that the macro fragmentation is completely removed from a current workbook, all you need to do is export your VBA modules to text files, create a brand new workbook, and import the modules into it.