Modified files in the libraries folder change back after copying

It sounds strange but I have some library files in C:\Program Files\Arduino\libraries modified. After copying this files to an other folder the content of the file is the original library file and not my modified. But in case I open the file in C:\Program Files\Arduino\libraries it has still my changes.

I do not know what here happens. I have spend nearly a day to solve a problem I can not imagine why it is not working but it could have to do with this. I had on this laptop a very old < 00something [edit: it was 0023 ;-] version of Arduino installed before and my sketchbook folder points still to files from this first installation years ago.

But I do not know what’s going on here. The setting is: Win7 with a 1.5.5 version installed and some other Arduino versions simply copied in a directory, so I thought I can it use independently from each other. I have also installed the 1.6.6 some weeks ago. Does it modify existing lib files?

I’m really lost!

Perhaps this leads to a solution http://superuser.com/questions/384107/why-cant-i-edit-a-program-files-file-on-windows-7

For example, if an application attempts to write to “C:\program files\appname\settings.ini” and the user doesn’t have permissions to write to that directory, the write will get redirected to “C:\Users\username\AppData\Local\VirtualStore\Program Files\appname\settings.ini”.

Seems that the original files are included and not the modified in \VirtualStore\Program Files... but why??