Update: The problem still remains, because every single add-on I download from Adobe Exchange can't be installed, throws the mentioned error and gives "validation failed" in ExtensionManager.log!
Nevertheless FYI I managed to install "Toolkit for Create JS" and "Animated SVG Exporter" from other sources.
What I did to install:
- downloaded version 1.2 of the Toolkit and installed without problems from: http://download.macromedia.com/pub/flashpro/ToolkitForCreateJS/1_2/Toolkit_for_CreateJS_v1 _2.zxp
- Version 1.0.3 that I got from Adobe Exchange was probably older than Version 1.1 that came with the latest regular update of Flash CS6. So version 1.2 was hopefully even a better choice
- downloaded version 3.36 of SVG Exporter and installed with accepting a self-signed certificate from:
- there it states: The last version that works in CS5.5 and CS6 is v3.36
- from Adobe Exchange I got version 3.46 that obviously doesn't work in CS6
Why is it just a workaround and not the solution:
Adobe Exchange still has plenty of great add-ons that should be compatible with CS6 and that I can't get from different sources. Unfortunately I couldn't find a way to install them so far.
It seems to be problem of security features:
- Could it have anything to do with certificates in the Mac's keychain?
- Is my Adobe ID "bundled" with add-ons I download from Adobe Exchange and how can I find out which one?
- How can I analyze the opm.db or find out with what Adobe ID my installed CS6 is associated with (I guess I still have a second Adobe ID from an old Macromedia account)?
- Are there any better ways to debug the problem besides the detailed ExtensionManager.log?
- Any suggestions?
Update: My problem is solved! The "An unexpected error occurred while attempting to verify this extension." has gone if installing add-ons through Adobe Extension Manager CS6!
How I got rid of the error message:
I had an alias "Adobe Application Manager" in my Applications-Folder that pointed towards /Applications/Utilities/Adobe Application Manager/core/Adobe Application Manager.app. The CFBundleVersion string inside the info.plist was 18.104.22.168. I have have no idea when or why it was installed on my system. Starting this "Adobe Application Manager.app" lead to an update to a newer version 10.0.0.49. Afterwards a menu bar application popped up, asking to log in to Creative Cloud with my Adobe ID. I did NOT log in, because I do not even have a Creative Cloud subscription, but quitting the menu bar app by pressing "quit" in the app's gearwheel icon. Then I gave Extension Manager another try. After selecting an Adobe Exchange add-on to install in Extension Manager, the "Adobe Application Manager" popped up, asking me for my Adobe ID. Oddly it's default was my second (old) Adobe ID, that I replaced with my up to date Adobe ID and password.
A few seconds later Extension Manager installed the add-on without any error and no hassle with my InDesign standard add-ons.
As a side effect I got a new folder "/Applications/Utilities/Adobe Creative Cloud" with about 330 MB of stuff I didn't really seem to need. I luckily found an Uninstaller in "/Applications/Utilities/Adobe Creative Cloud/Utils/Creative Cloud Uninstaller.app" that deleted the "useless" stuff with no known negative side-effect to the functionality of my CS6 nor the Adobe Extension Manager CS6.
Thanks to everyone that was willing to help, taking the time to read this thread. I'll mark this as right answer for people digging into the same problem!