The only correct hint I found was in a screenshot of Excel settings (but these were in German). Is it at all possible to deactivate macros or macro sheets in Excel 4.0 or to always prevent them from being executed?
However, the option shown in the screenshot is not to be found in my Excel settings.
In Trust Center settings, when a separate check box for Excel 4.0 macros does not exist, disabling all macros will also disable Excel 4.0 macros.