Adobe Acrobat DC Update Failed

Hi,

I have a big problem with updating to Adobe Acrobat DC (Windows 8.1, 64 bit); I am trying to install it since three days now. When installing out of the CCInstaller, the following error appears:

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Exit Code: 7

Please see specific errors below for troubleshooting. For example, ERROR:

-------------------------------------- Summary --------------------------------------

- 0 fatal error(s), 1 error(s)

----------- Payload: Adobe Acrobat DC 15.7.20033.0 Adobe Acrobat\Setup.exe_15.007.20033 -----------

ERROR: Third party payload installer Adobe Acrobat\Setup.exe failed with exit code: 1603

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I already tried all of these recommended steps: Error 1603: A fatal error occurred during installation, but it did not work. I also tried to install it via the direct DCInstaller, but there is is always an error when installing. Sometimes this one:

(Installation failure of the Acrobat License Module. Possible solutions under http://...)

Sometimes this one:

It's really frustrating... Any additional idea?

Thanks very much in advance,

Henrik