I've created an msi installer for our product version 6.0.0.101 which works fine. We now have a minor update so I've rebuilt my installer for the new version 6.0.1.109 which works fine. I now want to create a patch to upgrade users of the previous version to the latest version. I've created a patch which works fine under Windows 7 but when I try and use the same patch under Windows XP I get "Error 1328. Error applying patch to file... It has probably been updated by other means...". It hasn't been touched by anything else.
I've also tried creating a new msi installer from scratch which only installs the .exe and simulated the steps I followed for my original installer and I have the same problem. Patch works fine for Win 7, error 1328 for XP.
If I set the patch to include the whole files then it works for XP but I'd rather not do this (keeps file size down).
