I have the same problem with AI 12.8. Have you already encountered a solution for that?
Basically we try to create patches for the last version, we have just released. The differences in the project files are quite small (because just released). Should I also provide you our project files?
We are not able to replicate this behaviour on our end.
In order to further investigate this issue, can you please send us a download link for the old setup package and the upgraded version to support at advancedinstaller dot com so we can try to build the patch on our end? Also, please give us a detailed test case scenario. You can also send us the .AIP(project file) of the old version, new version and the patch project. If it contains confidential information you can send us a small test project which reproduce this behavior.
We further investigated this problem and finally we were able to replicate it. It seems the related misleading build error is thrown when you try to build an updates configuration project whose updates entries points to an updates setup file path from disk which is unavailable or invalid. We'll improve the error message we throw in this case in a future version of Advanced Installer, thank you for bringing this to our attention. We'll notify you when an improvement will be out.
In the meantime just proceed like this:
1. open you updates configuration project in AI
2. select your update entry in "Updates" page
3. go to "Update Installer" tab and make sure that in the "File path" field is a valid path pointing to your updates setup package (just pick again the updates setup using the [...] picker button)
4. save and rebuild the project
I changed the version number in the project and opened the patch project with an older version of AI (in this case 12.0). I could easily start to build the project, then it fails, because one of the MSI source files was missing. I fixed all the missing sources, then the project build fine.
After that try I opened the patch project again with 12.8 and it works. To make sure, its the missing source file, I renamed the folder and build again - with the same error message as above. So the problem is, that missing files are causing the issue described above. Please fix this in a future version, its a pity to not find out whats missing.
I guess, you don't need my project files anymore.
@cf454: Try to open and build the patch with an older version of AI (fix the project file for that) and find your missing resources. After fixing all issues you can build the patch with the older or latest version of AI.
@Dan: Sorry, I just noticed, that you wrote an additional message to the post, its basically the explanation of my findings.