Extra space while installing .msi

Question

I have extra space in my custom made .msi. The data to be installed has about 600MB and the installer says it needs 1.4 GB.Switching to a different location then the predetermined one (e.g from C:\Program Files\My_App to F:\My_App) shows that it always need approximately 800 MB on the Windows partition, which is in my case the extra space. Any thoughts on why is this happening?

Also can this cause an installation error on a 64-bit OS? I've only installed it on a 32-bit OS and everything is fine, but one of my colleagues is having problems installing it on the above mentioned type.

Answer 1

I think this may have to do with adding in possible caching. If you were to cache the full msi plus the installed product, that could account for the problem.

See this page for more info.

Answer 2

How about not including the 600 MB data into the MSI? You can still distribute a single installer by packaging the MSI + all data files (+ bootstrapper, if any) into one self-extracting exe file. IExpress is a good tool for that and is included in Windows. You might even benefit from a better compression afaik.