There are a lot of reasons possible. At first make sure that really only a single macro could be run - means not triggering multiple ones through a button or similar within a chain of actions. If multiple routines/functions are needed the macro itself should call them to ensure that they run in the right order.
Further for all interactions with the UI or the OS you should set WaitForIdle and Sleep statements to ensure that Qlik has enough time to calculate the UI respectively the OS to perform the I/O actions.
If this is done and there are further issues you should implement an error-logging - in a more simple way it would be just some msgbox with err.number and err.description and/or your variable/selection-values and more extended to write all those things with a timestamp into a text-file.
- Marcus
