I think I may have found the bug in the Adobe Air installer. At least this worked for me on Win10...
When you upgrade Air it has to download an installer file and this is normally placed into the Downloads folder and named AdobeAIRInstaller.exe. If there is already a version of that file in the Downloads folder from a previous install, then the new installer file will be named something like AdobeAIRInstaller (1).exe.
I think what is happening is that when the new installer is downloaded it starts out by running AdobeAIRInstaller (1).exe, but then sometime during the install process it calls back to the normal executable name AdobeAIRInstaller.exe which is actually an old version of the installer. It then gets totally messed up with the install, which in my view is an Adobe Air bug.
The way I solved this is two step. Not positive that both are necessary, but it is what worked for me.
- Goto the Downloads folder and find all AdobeAIRInstaller* files. Delete all but the latest file and then rename that file to make sure it is AdobeAIRInstaller.exe and not something like AdobeAIRInstaller (1).exe.
- Goto the folder C:\Program Files (x86)\Common Files\Adobe AIR\Versions and delete the 1.0 folder in the Versions folder.
- Run the AdobeAIRInstaller.exe file.
Hopefully this helps someone...