X1 Search Index is up-to-date button

Hello,

Since a few days at the top left corner of my Windows 7/64 desktop suddenly a small "X1 Search Index is up-to-date" button appears and I don't succeed in removing it. It just happened two hours after booting my PC. Could someone please tell me why that happens and how to make disappear the button.

Thank you in advance and kind regards,

Anselm

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