Stopping Excel from Deleting Macros from a Workbook

Chris has a very large (350 GB) workbook. There are many times, when opening the workbook, that the macros it should contain are stripped out and the workbook is deemed corrupt. In those cases, Chris has to rely on the frequent backups he makes. He wonders how he can stop this from happening.

When I read the question from Chris, my immediate reaction was to question the size of the workbook file. It seems very doubtful that a workbook is actually 350 GB, as limits on both Access and SQL Server files is in the 2 GB neighborhood. This caused me to go look up the limits published by Microsoft:

https://support.microsoft.com/en-us/office/excel-specifications-and-limits-1672b34d-7043-467e-8e27-269d656771c3

The page indicates that there are limits similar to Access and SQL Server when running the 32-bit version of Excel. If using the 64-bit version, however, the official word is that you are limited only by "available memory and system resources." So, theoretically, a 350 GB file could be opened.

The germane question, however, is should you open such a workbook, even if you could. Feelings among ExcelTips subscribers are mixed on the answer, with most leaning toward an emphatic "no way!" Most long-time Excel users understand that the larger the workbook file, the more susceptible the file is to problems and corruption.

This tendency would explain Chris' experience with the macros getting stripped off and the workbook showing as being corrupt. It should be noted, as well, that it isn't the macros getting stripped off that corrupts the workbook, but the workbook becoming corrupted that causes the macros to get stripped off—Excel, in the process of trying to recover a workbook it considers corrupt, will routinely strip off the macros.

There is a two-fold solution to this problem. First, open a non-corrupt copy of the workbook and transfer the macro modules to a different, blank, macro-enabled workbook. You can then save the workbook as an add-in, which you can then load back into Excel. In that way, even if your very large workbook becomes corrupted (again), you still have your macros available through your add-in.

The second thing to do is to find ways to make your workbook smaller. This will obviously take some rethinking of how you store your data and what is contained in your workbook. Perhaps, for instance, you could have one workbook for each year of data, for each project, or for each department. How you divvy up the data will obviously depend on the nature of your data, and it will take some work. If you combine this with the previous suggestion to make your macros into an add-in, then your macros will be available in all of your smaller, more manageable, and less corruptible workbooks.

It is worth revisiting my original speculation—is Chris's workbook really 350 GB, or was that a type and the workbook is a much smaller 350 MB? If the smaller workbook is really what Chris is working with, then the same suggestions remain—spin your macros off to an add-in and divide your workbook data into a series of smaller workbooks.

Regardless of the workbook size—350 GB or 350 MB—when dividing up the data into separate workbooks, don't do so by copying the original workbook and trimming it back. If the workbook is corrupted in some way, you'll want to reconstruct the workbook from scratch, copying formulas and values, as necessary, from the problem worksheet. Don't copy entire worksheets, however, to the new workbooks, as that may end up copying the corruption you want to remove.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (12983) applies to Microsoft Excel 2007, 2010, 2013, 2016, 2019, Excel in Microsoft 365, and 2021.