Same patch installed several times?

I hope this is the right place. In case, please, let me know if another
forum is more suitable for my question.

In the last few months I noticed a severe reduction of space on C-disk. I
analysed it and found out that it is due to the INSTALLER folder. In
particular, I have ten files with different names (xxxxx.msp) but EXACTLY
the same size, date, and time! I suspect that the updater tried to install
more time the same patch and now I have duplicates in INSTALLER folder. But
how can I check that? I cannot simply remove those files, because I do not
know which one I have to keep and I do not want to create an alignment
problem with the registry. Which is the best approach to remove useless
files and reobtain my space?

Thank you in advance.

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Dario de Judicibus - Italy (EU)
Site: http://www.dejudicibus.it
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