Problem with experimental update (17/06/15)

Hi all,

yesterday I saw that there was a new miktex update. When I tried to 
update only one server was available.
I know this is strange but I did it. I must admit it's my fault.

The first list of updated packages only allowed me to charge 
miktex-bin-x64-2.9 which was downloaded an installed without problems.
But when I tried to update again for downloading all other updated 
packages, miktex (or windows) complains saying that certain link to 
program "copystart.exe" is not correct. And now, neither miktex-update 
nor miktex package manager work.

There's no problem with pdflatex and I can work with it. The problem 
seems to be only with some miktex binaries.

Do you know if it's possible to repair the system without installing 
miktex again?

Thank you,

Ignasi

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