It wasn't a complete failure, more the opposite, a great success. Until Microsoft moved their HQ to Munich and some old conservatives started complaining about some miniscule problems. Of course, there were issues, every software has issues. And Bavaria's IT is very problematic in general, having many issues overall. But those were all solvable, at a cheaper price than the rollback to Windows had cost at the end.

And fun fact: now 4 Years later, after the reigning political party has changed, they are switching back to Open Source and probably Linux.