I love Macrium Reflect - not denying that. It works very well for imaging drives (except when it doesn't - but that's usually a hardware issue with the drive itself).
But lately it's been acting weird for me. A few times a day, I would notice that there was a nearly empty window that had opened itself up and only had a "close" button.
Today I finally took the time to use the drop down menu at the top and realized that it was a window opened by a certain hotkey combination - alt-ctrl-m.
This may not be a common one for many of you, but I use that combo a few times a day to <comment> in Google Sheets.
I just unchecked the "use hotkey" radio box, and I anticipate all should be well with the world again.