Today I tried do update Lightroom. Normal update ended with U44M1P7 error and downgrade to 6.0.
I tried all the help page ("Installation failed" error U44M1P7 with Adobe Creative Cloud or Adobe Creative Suite 6 updates) including reinstalling Lightroom (with restart after each operation). Nothing helped. I can't upgrade to 6.6, and now even I don't have 6.5.1, but old 6.0.
I'm using Windows 10 Professional, Polish version.